21892457 has 4 divisors (see below), whose sum is σ = 22109316. Its totient is φ = 21675600.

The previous prime is 21892441. The next prime is 21892469. The reversal of 21892457 is 75429812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10995856 + 10896601 = 3316^2 + 3301^2 .

It is a cyclic number.

It is not a de Polignac number, because 21892457 - 2⁴ = 21892441 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21892457.

It is not an unprimeable number, because it can be changed into a prime (21892357) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 108278 + ... + 108479.

It is an arithmetic number, because the mean of its divisors is an integer number (5527329).

Almost surely, 2^21892457 is an apocalyptic number.

It is an amenable number.

21892457 is a deficient number, since it is larger than the sum of its proper divisors (216859).

21892457 is a wasteful number, since it uses less digits than its factorization.

21892457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 216858.

The product of its digits is 40320, while the sum is 38.

The square root of 21892457 is about 4678.9375930867. The cubic root of 21892457 is about 279.7466117498.

The spelling of 21892457 in words is "twenty-one million, eight hundred ninety-two thousand, four hundred fifty-seven".