21797031 has 8 divisors (see below), whose sum is σ = 30326400. Its totient is φ = 13899512.

The previous prime is 21797023. The next prime is 21797053. The reversal of 21797031 is 13079712.

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 21797031 - 2³ = 21797023 is a prime.

It is a super-3 number, since 3×21797031³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a self number, because there is not a number n which added to its sum of digits gives 21797031.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21797131) 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, 157881 + ... + 158018.

It is an arithmetic number, because the mean of its divisors is an integer number (3790800).

Almost surely, 2^21797031 is an apocalyptic number.

21797031 is a deficient number, since it is larger than the sum of its proper divisors (8529369).

21797031 is a wasteful number, since it uses less digits than its factorization.

21797031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 315925.

The product of its (nonzero) digits is 2646, while the sum is 30.

The square root of 21797031 is about 4668.7290561779. The cubic root of 21797031 is about 279.3395616405.

The spelling of 21797031 in words is "twenty-one million, seven hundred ninety-seven thousand, thirty-one".