21954731 has 2 divisors, whose sum is σ = 21954732. Its totient is φ = 21954730.

The previous prime is 21954707. The next prime is 21954763. The reversal of 21954731 is 13745912.

It is an a-pointer prime, because the next prime (21954763) can be obtained adding 21954731 to its sum of digits (32).

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21954731 is a prime.

It is a super-2 number, since 2×21954731² = 964020426564722, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21954631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10977365 + 10977366.

It is an arithmetic number, because the mean of its divisors is an integer number (10977366).

Almost surely, 2^21954731 is an apocalyptic number.

21954731 is a deficient number, since it is larger than the sum of its proper divisors (1).

21954731 is an equidigital number, since it uses as much as digits as its factorization.

21954731 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7560, while the sum is 32.

The square root of 21954731 is about 4685.5875832173. The cubic root of 21954731 is about 280.0116109131.

The spelling of 21954731 in words is "twenty-one million, nine hundred fifty-four thousand, seven hundred thirty-one".