21754980 has 120 divisors (see below), whose sum is σ = 73567032. Its totient is φ = 5349888.

The previous prime is 21754961. The next prime is 21754991. The reversal of 21754980 is 8945712.

It can be written as a sum of positive squares in 4 ways, for example, as 3709476 + 18045504 = 1926^2 + 4248^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

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 39 ways as a sum of consecutive naturals, for example, 20544 + ... + 21576.

Almost surely, 2^21754980 is an apocalyptic number.

21754980 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 21754980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36783516).

21754980 is an abundant number, since it is smaller than the sum of its proper divisors (51812052).

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

21754980 is a wasteful number, since it uses less digits than its factorization.

21754980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1067 (or 1056 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 21754980 is about 4664.2234080284. The cubic root of 21754980 is about 279.1598113215.

The spelling of 21754980 in words is "twenty-one million, seven hundred fifty-four thousand, nine hundred eighty".