55785243721 has 27 divisors (see below), whose sum is σ = 60988414599. Its totient is φ = 51016824000.

The previous prime is 55785243667. The next prime is 55785243727. The reversal of 55785243721 is 12734258755.

The square root of 55785243721 is 236189.

It is a perfect power (a square), and thus also a powerful number.

55785243721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 55230170121 + 555073600 = 235011^2 + 23560^2 .

It is not a de Polignac number, because 55785243721 - 2²⁵ = 55751689289 is a prime.

It is a super-2 number, since 2×55785243721² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (55785243727) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 139115121 + ... + 139115521.

Almost surely, 2^55785243721 is an apocalyptic number.

55785243721 is the 236189-th square number.

55785243721 is the 118095-th centered octagonal number.

It is an amenable number.

55785243721 is a deficient number, since it is larger than the sum of its proper divisors (5203170878).

55785243721 is an frugal number, since it uses more digits than its factorization.

55785243721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 902 (or 451 counting only the distinct ones).

The product of its digits is 2352000, while the sum is 49.

Multiplying 55785243721 by its sum of digits (49), we get a square (2733476942329 = 1653323²).

The spelling of 55785243721 in words is "fifty-five billion, seven hundred eighty-five million, two hundred forty-three thousand, seven hundred twenty-one".