21544931 has 2 divisors, whose sum is σ = 21544932. Its totient is φ = 21544930.

The previous prime is 21544903. The next prime is 21544937. The reversal of 21544931 is 13944512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21544931 - 2⁶ = 21544867 is a prime.

It is a super-2 number, since 2×21544931² = 928368103589522, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21544894 and 21544903.

It is not a weakly prime, because it can be changed into another prime (21544937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10772465 + 10772466.

It is an arithmetic number, because the mean of its divisors is an integer number (10772466).

Almost surely, 2^21544931 is an apocalyptic number.

21544931 is a deficient number, since it is larger than the sum of its proper divisors (1).

21544931 is an equidigital number, since it uses as much as digits as its factorization.

21544931 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4320, while the sum is 29.

The square root of 21544931 is about 4641.6517534171. The cubic root of 21544931 is about 278.2584548438.

The spelling of 21544931 in words is "twenty-one million, five hundred forty-four thousand, nine hundred thirty-one".