21234931 has 4 divisors (see below), whose sum is σ = 21967200. Its totient is φ = 20502664.

The previous prime is 21234923. The next prime is 21234937. The reversal of 21234931 is 13943212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21234931 - 2³ = 21234923 is a prime.

It is a super-2 number, since 2×21234931² = 901844589149522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21234896 and 21234905.

It is not an unprimeable number, because it can be changed into a prime (21234937) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 366091 + ... + 366148.

It is an arithmetic number, because the mean of its divisors is an integer number (5491800).

Almost surely, 2^21234931 is an apocalyptic number.

21234931 is a deficient number, since it is larger than the sum of its proper divisors (732269).

21234931 is an equidigital number, since it uses as much as digits as its factorization.

21234931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 732268.

The product of its digits is 1296, while the sum is 25.

The square root of 21234931 is about 4608.1374762479. The cubic root of 21234931 is about 276.9174251122.

The spelling of 21234931 in words is "twenty-one million, two hundred thirty-four thousand, nine hundred thirty-one".