21957011 has 8 divisors (see below), whose sum is σ = 22391424. Its totient is φ = 21525120.

The previous prime is 21956983. The next prime is 21957043. The reversal of 21957011 is 11075912.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21957011 is a prime.

It is a super-2 number, since 2×21957011² = 964220664108242, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21957071) 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, 35870 + ... + 36476.

It is an arithmetic number, because the mean of its divisors is an integer number (2798928).

Almost surely, 2^21957011 is an apocalyptic number.

21957011 is a deficient number, since it is larger than the sum of its proper divisors (434413).

21957011 is an equidigital number, since it uses as much as digits as its factorization.

21957011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1261.

The product of its (nonzero) digits is 630, while the sum is 26.

The square root of 21957011 is about 4685.8308761627. The cubic root of 21957011 is about 280.0213036512.

The spelling of 21957011 in words is "twenty-one million, nine hundred fifty-seven thousand, eleven".