21023120899 has 4 divisors (see below), whose sum is σ = 22934313720. Its totient is φ = 19111928080.

The previous prime is 21023120891. The next prime is 21023120903. The reversal of 21023120899 is 99802132012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21023120899 - 2³ = 21023120891 is a prime.

It is a super-2 number, since 2×21023120899² (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 (21023120891) 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, 955596394 + ... + 955596415.

It is an arithmetic number, because the mean of its divisors is an integer number (5733578430).

Almost surely, 2^21023120899 is an apocalyptic number.

21023120899 is a deficient number, since it is larger than the sum of its proper divisors (1911192821).

21023120899 is a wasteful number, since it uses less digits than its factorization.

21023120899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1911192820.

The product of its (nonzero) digits is 15552, while the sum is 37.

The spelling of 21023120899 in words is "twenty-one billion, twenty-three million, one hundred twenty thousand, eight hundred ninety-nine".