21957061 has 8 divisors (see below), whose sum is σ = 25261184. Its totient is φ = 18694800.

The previous prime is 21957053. The next prime is 21957071. The reversal of 21957061 is 16075912.

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 21957061 - 2³ = 21957053 is a prime.

It is a super-2 number, since 2×21957061² = 964225055515442, which contains 22 as substring.

It is a Duffinian number.

It is a congruent 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, 9330 + ... + 11443.

It is an arithmetic number, because the mean of its divisors is an integer number (3157648).

Almost surely, 2^21957061 is an apocalyptic number.

It is an amenable number.

21957061 is a deficient number, since it is larger than the sum of its proper divisors (3304123).

21957061 is a wasteful number, since it uses less digits than its factorization.

21957061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20931.

The product of its (nonzero) digits is 3780, while the sum is 31.

The square root of 21957061 is about 4685.8362113928. The cubic root of 21957061 is about 280.0215162037.

The spelling of 21957061 in words is "twenty-one million, nine hundred fifty-seven thousand, sixty-one".