21575959 has 2 divisors, whose sum is σ = 21575960. Its totient is φ = 21575958.

The previous prime is 21575951. The next prime is 21575987. The reversal of 21575959 is 95957512.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21575959 - 2³ = 21575951 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21575951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10787979 + 10787980.

It is an arithmetic number, because the mean of its divisors is an integer number (10787980).

Almost surely, 2^21575959 is an apocalyptic number.

21575959 is a deficient number, since it is larger than the sum of its proper divisors (1).

21575959 is an equidigital number, since it uses as much as digits as its factorization.

21575959 is an evil number, because the sum of its binary digits is even.

The product of its digits is 141750, while the sum is 43.

The square root of 21575959 is about 4644.9928955812. The cubic root of 21575959 is about 278.3919690330.

The spelling of 21575959 in words is "twenty-one million, five hundred seventy-five thousand, nine hundred fifty-nine".