61756723081 has 3 divisors (see below), whose sum is σ = 61756971591. Its totient is φ = 61756474572.

The previous prime is 61756723043. The next prime is 61756723087. The reversal of 61756723081 is 18032765716.

The square root of 61756723081 is 248509.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 1388233081 + 60368490000 = 37259^2 + 245700^2 .

It is not a de Polignac number, because 61756723081 - 2⁹ = 61756722569 is a prime.

It is a super-2 number, since 2×61756723081² (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 (61756723087) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 124255 + ... + 372763.

It is an arithmetic number, because the mean of its divisors is an integer number (20585657197).

Almost surely, 2^61756723081 is an apocalyptic number.

61756723081 is the 248509-th square number.

61756723081 is the 124255-th centered octagonal number.

It is an amenable number.

61756723081 is a deficient number, since it is larger than the sum of its proper divisors (248510).

61756723081 is an frugal number, since it uses more digits than its factorization.

61756723081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 497018 (or 248509 counting only the distinct ones).

The product of its (nonzero) digits is 423360, while the sum is 46.

The spelling of 61756723081 in words is "sixty-one billion, seven hundred fifty-six million, seven hundred twenty-three thousand, eighty-one".