21768231 has 8 divisors (see below), whose sum is σ = 29960704. Its totient is φ = 14043960.

The previous prime is 21768223. The next prime is 21768251. The reversal of 21768231 is 13286712.

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

It is not a de Polignac number, because 21768231 - 2³ = 21768223 is a prime.

It is a super-2 number, since 2×21768231² = 947711761738722, 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 (21768221) 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, 116941 + ... + 117126.

It is an arithmetic number, because the mean of its divisors is an integer number (3745088).

Almost surely, 2^21768231 is an apocalyptic number.

21768231 is a deficient number, since it is larger than the sum of its proper divisors (8192473).

21768231 is a wasteful number, since it uses less digits than its factorization.

21768231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234101.

The product of its digits is 4032, while the sum is 30.

The square root of 21768231 is about 4665.6436854951. The cubic root of 21768231 is about 279.2164787429.

The spelling of 21768231 in words is "twenty-one million, seven hundred sixty-eight thousand, two hundred thirty-one".