21738057 has 16 divisors (see below), whose sum is σ = 31838400. Its totient is φ = 13083200.

The previous prime is 21738049. The next prime is 21738089. The reversal of 21738057 is 75083712.

It is a cyclic number.

It is not a de Polignac number, because 21738057 - 2³ = 21738049 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (21738007) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2707 + ... + 7127.

It is an arithmetic number, because the mean of its divisors is an integer number (1989900).

Almost surely, 2^21738057 is an apocalyptic number.

It is an amenable number.

21738057 is a deficient number, since it is larger than the sum of its proper divisors (10100343).

21738057 is a wasteful number, since it uses less digits than its factorization.

21738057 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4584.

The product of its (nonzero) digits is 11760, while the sum is 33.

The square root of 21738057 is about 4662.4089267245. The cubic root of 21738057 is about 279.0874072559.

The spelling of 21738057 in words is "twenty-one million, seven hundred thirty-eight thousand, fifty-seven".