55721015172 has 18 divisors (see below), whose sum is σ = 140850343998. Its totient is φ = 18573671712.

The previous prime is 55721015137. The next prime is 55721015213. The reversal of 55721015172 is 27151012755.

55721015172 is a `hidden beast` number, since 5 + 572 + 1 + 0 + 15 + 1 + 72 = 666.

It can be written as a sum of positive squares in only one way, i.e., 47082056256 + 8638958916 = 216984^2 + 92946^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 1547805977 = 55721015172 / (5 + 5 + 7 + 2 + 1 + 0 + 1 + 5 + 1 + 7 + 2).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 773902953 + ... + 773903024.

It is an arithmetic number, because the mean of its divisors is an integer number (7825019111).

Almost surely, 2^55721015172 is an apocalyptic number.

It is an amenable number.

55721015172 is an abundant number, since it is smaller than the sum of its proper divisors (85129328826).

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

55721015172 is a wasteful number, since it uses less digits than its factorization.

55721015172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1547805987 (or 1547805982 counting only the distinct ones).

The product of its (nonzero) digits is 24500, while the sum is 36.

The spelling of 55721015172 in words is "fifty-five billion, seven hundred twenty-one million, fifteen thousand, one hundred seventy-two".