21366231 has 8 divisors (see below), whose sum is σ = 28706304. Its totient is φ = 14135160.

The previous prime is 21366221. The next prime is 21366239. The reversal of 21366231 is 13266312.

It is a happy number.

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

It is not a de Polignac number, because 21366231 - 2¹⁴ = 21349847 is a prime.

It is a super-2 number, since 2×21366231² = 913031654290722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21366239) 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, 26791 + ... + 27576.

It is an arithmetic number, because the mean of its divisors is an integer number (3588288).

Almost surely, 2^21366231 is an apocalyptic number.

21366231 is a deficient number, since it is larger than the sum of its proper divisors (7340073).

21366231 is a wasteful number, since it uses less digits than its factorization.

21366231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54501.

The product of its digits is 1296, while the sum is 24.

The square root of 21366231 is about 4622.3620585151. The cubic root of 21366231 is about 277.4869988228.

The spelling of 21366231 in words is "twenty-one million, three hundred sixty-six thousand, two hundred thirty-one".