72773772661 has 4 divisors (see below), whose sum is σ = 72774409824. Its totient is φ = 72773135500.

The previous prime is 72773772653. The next prime is 72773772667. The reversal of 72773772661 is 16627737727.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 72773772661 - 2³ = 72773772653 is a prime.

It is a super-2 number, since 2×72773772661² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72773772667) 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, 94915 + ... + 393136.

It is an arithmetic number, because the mean of its divisors is an integer number (18193602456).

Almost surely, 2^72773772661 is an apocalyptic number.

It is an amenable number.

72773772661 is a deficient number, since it is larger than the sum of its proper divisors (637163).

72773772661 is a wasteful number, since it uses less digits than its factorization.

72773772661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 637162.

The product of its digits is 7260624, while the sum is 55.

The spelling of 72773772661 in words is "seventy-two billion, seven hundred seventy-three million, seven hundred seventy-two thousand, six hundred sixty-one".