21957029 has 8 divisors (see below), whose sum is σ = 22210848. Its totient is φ = 21705040.

The previous prime is 21956983. The next prime is 21957043. The reversal of 21957029 is 92075912.

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-21957029 is a prime.

It is a super-2 number, since 2×21957029² = 964222245013682, which contains 22 as substring.

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 21957029.

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 44474 + ... + 44964.

It is an arithmetic number, because the mean of its divisors is an integer number (2776356).

Almost surely, 2^21957029 is an apocalyptic number.

It is an amenable number.

21957029 is a deficient number, since it is larger than the sum of its proper divisors (253819).

21957029 is a wasteful number, since it uses less digits than its factorization.

21957029 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 915.

The product of its (nonzero) digits is 11340, while the sum is 35.

The square root of 21957029 is about 4685.8327968463. The cubic root of 21957029 is about 280.0213801701.

The spelling of 21957029 in words is "twenty-one million, nine hundred fifty-seven thousand, twenty-nine".