21957089 has 16 divisors (see below), whose sum is σ = 28321920. Its totient is φ = 16517760.

The previous prime is 21957079. The next prime is 21957107. The reversal of 21957089 is 98075912.

It is not a de Polignac number, because 21957089 - 2¹² = 21952993 is a prime.

It is a super-3 number, since 3×21957089³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (21957049) 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, 2684 + ... + 7149.

It is an arithmetic number, because the mean of its divisors is an integer number (1770120).

Almost surely, 2^21957089 is an apocalyptic number.

21957089 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21957089 is a deficient number, since it is larger than the sum of its proper divisors (6364831).

21957089 is a wasteful number, since it uses less digits than its factorization.

21957089 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9880.

The product of its (nonzero) digits is 45360, while the sum is 41.

The square root of 21957089 is about 4685.8391991190. The cubic root of 21957089 is about 280.0216352330.

The spelling of 21957089 in words is "twenty-one million, nine hundred fifty-seven thousand, eighty-nine".