55781606772 has 30 divisors (see below), whose sum is σ = 145824139538. Its totient is φ = 18593868816.

The previous prime is 55781606753. The next prime is 55781606827. The reversal of 55781606772 is 27760618755.

It is a happy number.

55781606772 is a `hidden beast` number, since 5 + 578 + 1 + 6 + 0 + 67 + 7 + 2 = 666.

It can be written as a sum of positive squares in only one way, i.e., 43574892516 + 12206714256 = 208746^2 + 110484^2 .

It is a super-2 number, since 2×55781606772² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 86082403 + ... + 86083050.

Almost surely, 2^55781606772 is an apocalyptic number.

It is an amenable number.

55781606772 is an abundant number, since it is smaller than the sum of its proper divisors (90042532766).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

55781606772 is a wasteful number, since it uses less digits than its factorization.

55781606772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172165469 (or 172165458 counting only the distinct ones).

The product of its (nonzero) digits is 4939200, while the sum is 54.

The spelling of 55781606772 in words is "fifty-five billion, seven hundred eighty-one million, six hundred six thousand, seven hundred seventy-two".