21773713931 has 4 divisors (see below), whose sum is σ = 21917910864. Its totient is φ = 21629517000.

The previous prime is 21773713891. The next prime is 21773713933. The reversal of 21773713931 is 13931737712.

It is a happy number.

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 21773713931 - 2⁶ = 21773713867 is a prime.

It is a super-2 number, since 2×21773713931² (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 (21773713933) 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, 72098240 + ... + 72098541.

It is an arithmetic number, because the mean of its divisors is an integer number (5479477716).

Almost surely, 2^21773713931 is an apocalyptic number.

21773713931 is a deficient number, since it is larger than the sum of its proper divisors (144196933).

21773713931 is a wasteful number, since it uses less digits than its factorization.

21773713931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144196932.

The product of its digits is 166698, while the sum is 44.

The spelling of 21773713931 in words is "twenty-one billion, seven hundred seventy-three million, seven hundred thirteen thousand, nine hundred thirty-one".