21381480 has 48 divisors (see below), whose sum is σ = 69490980. Its totient is φ = 5701632.

The previous prime is 21381469. The next prime is 21381491. The reversal of 21381480 is 8418312.

It is an interprime number because it is at equal distance from previous prime (21381469) and next prime (21381491).

It can be written as a sum of positive squares in 2 ways, for example, as 20304036 + 1077444 = 4506^2 + 1038^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 29337 + ... + 30056.

Almost surely, 2^21381480 is an apocalyptic number.

21381480 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21381480 is an abundant number, since it is smaller than the sum of its proper divisors (48109500).

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

21381480 is a wasteful number, since it uses less digits than its factorization.

21381480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59410 (or 59403 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 21381480 is about 4624.0112456611. The cubic root of 21381480 is about 277.5529969391.

Adding to 21381480 its reverse (8418312), we get a palindrome (29799792).

It can be divided in two parts, 21 and 381480, that added together give a triangular number (381501 = T₈₇₃).

The spelling of 21381480 in words is "twenty-one million, three hundred eighty-one thousand, four hundred eighty".