21031159897 has 4 divisors (see below), whose sum is σ = 22943083536. Its totient is φ = 19119236260.

The previous prime is 21031159859. The next prime is 21031159931. The reversal of 21031159897 is 79895113012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21031159897 - 2¹⁵ = 21031127129 is a prime.

It is a super-2 number, since 2×21031159897² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21031159817) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 955961803 + ... + 955961824.

It is an arithmetic number, because the mean of its divisors is an integer number (5735770884).

Almost surely, 2^21031159897 is an apocalyptic number.

It is an amenable number.

21031159897 is a deficient number, since it is larger than the sum of its proper divisors (1911923639).

21031159897 is a wasteful number, since it uses less digits than its factorization.

21031159897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1911923638.

The product of its (nonzero) digits is 136080, while the sum is 46.

The spelling of 21031159897 in words is "twenty-one billion, thirty-one million, one hundred fifty-nine thousand, eight hundred ninety-seven".