21457967 has 2 divisors, whose sum is σ = 21457968. Its totient is φ = 21457966.

The previous prime is 21457963. The next prime is 21457981. The reversal of 21457967 is 76975412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21457967 - 2² = 21457963 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21457963) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10728983 + 10728984.

It is an arithmetic number, because the mean of its divisors is an integer number (10728984).

Almost surely, 2^21457967 is an apocalyptic number.

21457967 is a deficient number, since it is larger than the sum of its proper divisors (1).

21457967 is an equidigital number, since it uses as much as digits as its factorization.

21457967 is an evil number, because the sum of its binary digits is even.

The product of its digits is 105840, while the sum is 41.

The square root of 21457967 is about 4632.2744953208. The cubic root of 21457967 is about 277.8835623347.

The spelling of 21457967 in words is "twenty-one million, four hundred fifty-seven thousand, nine hundred sixty-seven".