21485680 has 40 divisors (see below), whose sum is σ = 52130592. Its totient is φ = 8219904.

The previous prime is 21485677. The next prime is 21485687. The reversal of 21485680 is 8658412.

It is a tau number, because it is divible by the number of its divisors (40).

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

It is a plaindrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21485687) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3999 + ... + 7678.

Almost surely, 2^21485680 is an apocalyptic number.

21485680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21485680 is an abundant number, since it is smaller than the sum of its proper divisors (30644912).

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

21485680 is a wasteful number, since it uses less digits than its factorization.

21485680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11713 (or 11707 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 34.

The square root of 21485680 is about 4635.2648252284. The cubic root of 21485680 is about 278.0031398986.

The spelling of 21485680 in words is "twenty-one million, four hundred eighty-five thousand, six hundred eighty".