21350578973 has 4 divisors (see below), whose sum is σ = 21352702368. Its totient is φ = 21348455580.

The previous prime is 21350578927. The next prime is 21350578979. The reversal of 21350578973 is 37987505312.

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 21350578973 - 2²² = 21346384669 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 (21350578979) 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, 1046543 + ... + 1066748.

It is an arithmetic number, because the mean of its divisors is an integer number (5338175592).

Almost surely, 2^21350578973 is an apocalyptic number.

It is an amenable number.

21350578973 is a deficient number, since it is larger than the sum of its proper divisors (2123395).

21350578973 is a wasteful number, since it uses less digits than its factorization.

21350578973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2123394.

The product of its (nonzero) digits is 1587600, while the sum is 50.

The spelling of 21350578973 in words is "twenty-one billion, three hundred fifty million, five hundred seventy-eight thousand, nine hundred seventy-three".