21195897 has 8 divisors (see below), whose sum is σ = 29235840. Its totient is φ = 13643280.

The previous prime is 21195883. The next prime is 21195899. The reversal of 21195897 is 79859112.

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

It is not a de Polignac number, because 21195897 - 2⁸ = 21195641 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21195899) 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, 121729 + ... + 121902.

It is an arithmetic number, because the mean of its divisors is an integer number (3654480).

Almost surely, 2^21195897 is an apocalyptic number.

It is an amenable number.

21195897 is a deficient number, since it is larger than the sum of its proper divisors (8039943).

21195897 is a wasteful number, since it uses less digits than its factorization.

21195897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 243663.

The product of its digits is 45360, while the sum is 42.

The square root of 21195897 is about 4603.9001944004. The cubic root of 21195897 is about 276.7476447208.

The spelling of 21195897 in words is "twenty-one million, one hundred ninety-five thousand, eight hundred ninety-seven".