21915480 has 64 divisors (see below), whose sum is σ = 66175200. Its totient is φ = 5806080.

The previous prime is 21915463. The next prime is 21915497. The reversal of 21915480 is 8451912.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21915463) and next prime (21915497).

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21216 + ... + 22224.

Almost surely, 2^21915480 is an apocalyptic number.

21915480 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21915480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33087600).

21915480 is an abundant number, since it is smaller than the sum of its proper divisors (44259720).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21915480 is a wasteful number, since it uses less digits than its factorization.

21915480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1204 (or 1200 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 30.

The square root of 21915480 is about 4681.3972273243. The cubic root of 21915480 is about 279.8446417064.

Adding to 21915480 its sum of digits (30), we get a triangular number (21915510 = T₆₆₂₀).

The spelling of 21915480 in words is "twenty-one million, nine hundred fifteen thousand, four hundred eighty".