21957087 has 8 divisors (see below), whose sum is σ = 29473200. Its totient is φ = 14539520.

The previous prime is 21957079. The next prime is 21957107. The reversal of 21957087 is 78075912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21957087 - 2³ = 21957079 is a prime.

It is a super-2 number, since 2×21957087² = 964227339051138, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21957077) 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, 24114 + ... + 25007.

It is an arithmetic number, because the mean of its divisors is an integer number (3684150).

Almost surely, 2^21957087 is an apocalyptic number.

21957087 is a deficient number, since it is larger than the sum of its proper divisors (7516113).

21957087 is a wasteful number, since it uses less digits than its factorization.

21957087 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49273.

The product of its (nonzero) digits is 35280, while the sum is 39.

The square root of 21957087 is about 4685.8389857100. The cubic root of 21957087 is about 280.0216267309.

The spelling of 21957087 in words is "twenty-one million, nine hundred fifty-seven thousand, eighty-seven".