21453967 has 2 divisors, whose sum is σ = 21453968. Its totient is φ = 21453966.

The previous prime is 21453961. The next prime is 21453977. The reversal of 21453967 is 76935412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21453967 - 2¹¹ = 21451919 is a prime.

It is equal to p_1356868 and since 21453967 and 1356868 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21453961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10726983 + 10726984.

It is an arithmetic number, because the mean of its divisors is an integer number (10726984).

Almost surely, 2^21453967 is an apocalyptic number.

21453967 is a deficient number, since it is larger than the sum of its proper divisors (1).

21453967 is an equidigital number, since it uses as much as digits as its factorization.

21453967 is an evil number, because the sum of its binary digits is even.

The product of its digits is 45360, while the sum is 37.

The square root of 21453967 is about 4631.8427218549. The cubic root of 21453967 is about 277.8662944155.

The spelling of 21453967 in words is "twenty-one million, four hundred fifty-three thousand, nine hundred sixty-seven".