21057080 has 32 divisors (see below), whose sum is σ = 51686640. Its totient is φ = 7656960.

The previous prime is 21057061. The next prime is 21057083. The reversal of 21057080 is 8075012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21057083) 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, 23489 + ... + 24368.

Almost surely, 2^21057080 is an apocalyptic number.

21057080 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21057080 is an abundant number, since it is smaller than the sum of its proper divisors (30629560).

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

21057080 is a wasteful number, since it uses less digits than its factorization.

21057080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47879 (or 47875 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 23.

The square root of 21057080 is about 4588.7994072524. The cubic root of 21057080 is about 276.1421587901.

The spelling of 21057080 in words is "twenty-one million, fifty-seven thousand, eighty".