21205733351 has 16 divisors (see below), whose sum is σ = 24388080000. Its totient is φ = 18235562400.

The previous prime is 21205733293. The next prime is 21205733357. The reversal of 21205733351 is 15333750212.

It is a de Polignac number, because none of the positive numbers 2^k-21205733351 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 (21205733357) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 61400 + ... + 214898.

It is an arithmetic number, because the mean of its divisors is an integer number (1524255000).

Almost surely, 2^21205733351 is an apocalyptic number.

21205733351 is a deficient number, since it is larger than the sum of its proper divisors (3182346649).

21205733351 is a wasteful number, since it uses less digits than its factorization.

21205733351 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154190.

The product of its (nonzero) digits is 18900, while the sum is 32.

The spelling of 21205733351 in words is "twenty-one billion, two hundred five million, seven hundred thirty-three thousand, three hundred fifty-one".