21295857 has 8 divisors (see below), whose sum is σ = 30975840. Its totient is φ = 12906560.

The previous prime is 21295843. The next prime is 21295871. The reversal of 21295857 is 75859212.

It is an interprime number because it is at equal distance from previous prime (21295843) and next prime (21295871).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21295857 - 2⁸ = 21295601 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21295817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 322632 + ... + 322697.

It is an arithmetic number, because the mean of its divisors is an integer number (3871980).

Almost surely, 2^21295857 is an apocalyptic number.

It is an amenable number.

21295857 is a deficient number, since it is larger than the sum of its proper divisors (9679983).

21295857 is a wasteful number, since it uses less digits than its factorization.

21295857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 645343.

The product of its digits is 50400, while the sum is 39.

The square root of 21295857 is about 4614.7434381556. The cubic root of 21295857 is about 277.1820105598.

It can be divided in two parts, 212 and 95857, that added together give a palindrome (96069).

The spelling of 21295857 in words is "twenty-one million, two hundred ninety-five thousand, eight hundred fifty-seven".