21126931 has 8 divisors (see below), whose sum is σ = 24734304. Its totient is φ = 17666880.

The previous prime is 21126929. The next prime is 21126943. The reversal of 21126931 is 13962112.

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

It is not a de Polignac number, because 21126931 - 2¹ = 21126929 is a prime.

It is a super-2 number, since 2×21126931² = 892694426957522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21126896 and 21126905.

It is not an unprimeable number, because it can be changed into a prime (21126901) 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, 36520 + ... + 37093.

It is an arithmetic number, because the mean of its divisors is an integer number (3091788).

Almost surely, 2^21126931 is an apocalyptic number.

21126931 is a deficient number, since it is larger than the sum of its proper divisors (3607373).

21126931 is an equidigital number, since it uses as much as digits as its factorization.

21126931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73661.

The product of its digits is 648, while the sum is 25.

The square root of 21126931 is about 4596.4041380192. The cubic root of 21126931 is about 276.4471633576.

The spelling of 21126931 in words is "twenty-one million, one hundred twenty-six thousand, nine hundred thirty-one".