21077921953 has 4 divisors (see below), whose sum is σ = 22994096688. Its totient is φ = 19161747220.

The previous prime is 21077921951. The next prime is 21077921959. The reversal of 21077921953 is 35912977012.

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 not a de Polignac number, because 21077921953 - 2¹ = 21077921951 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21077921951) 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, 958087351 + ... + 958087372.

It is an arithmetic number, because the mean of its divisors is an integer number (5748524172).

Almost surely, 2^21077921953 is an apocalyptic number.

It is an amenable number.

21077921953 is a deficient number, since it is larger than the sum of its proper divisors (1916174735).

21077921953 is a wasteful number, since it uses less digits than its factorization.

21077921953 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1916174734.

The product of its (nonzero) digits is 238140, while the sum is 46.

The spelling of 21077921953 in words is "twenty-one billion, seventy-seven million, nine hundred twenty-one thousand, nine hundred fifty-three".