21127513021 has 4 divisors (see below), whose sum is σ = 21245544000. Its totient is φ = 21009482044.

The previous prime is 21127513007. The next prime is 21127513027. The reversal of 21127513021 is 12031572112.

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 21127513021 - 2³³ = 12537578429 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21127513027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 59015221 + ... + 59015578.

It is an arithmetic number, because the mean of its divisors is an integer number (5311386000).

Almost surely, 2^21127513021 is an apocalyptic number.

It is an amenable number.

21127513021 is a deficient number, since it is larger than the sum of its proper divisors (118030979).

21127513021 is a wasteful number, since it uses less digits than its factorization.

21127513021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118030978.

The product of its (nonzero) digits is 840, while the sum is 25.

The spelling of 21127513021 in words is "twenty-one billion, one hundred twenty-seven million, five hundred thirteen thousand, twenty-one".