61721565726 has 16 divisors (see below), whose sum is σ = 124930399104. Its totient is φ = 20325977304.

The previous prime is 61721565709. The next prime is 61721565739. The reversal of 61721565726 is 62756512716.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 61968946 + ... + 61969941.

It is an arithmetic number, because the mean of its divisors is an integer number (7808149944).

Almost surely, 2^61721565726 is an apocalyptic number.

61721565726 is an abundant number, since it is smaller than the sum of its proper divisors (63208833378).

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

61721565726 is a wasteful number, since it uses less digits than its factorization.

61721565726 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123938975.

The product of its digits is 1058400, while the sum is 48.

The spelling of 61721565726 in words is "sixty-one billion, seven hundred twenty-one million, five hundred sixty-five thousand, seven hundred twenty-six".