61111721671 has 64 divisors (see below), whose sum is σ = 86331119616. Its totient is φ = 42043415040.

The previous prime is 61111721633. The next prime is 61111721681. The reversal of 61111721671 is 17612711116.

It is not a de Polignac number, because 61111721671 - 2¹¹ = 61111719623 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61111721681) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2774815 + ... + 2796751.

It is an arithmetic number, because the mean of its divisors is an integer number (1348923744).

Almost surely, 2^61111721671 is an apocalyptic number.

61111721671 is a deficient number, since it is larger than the sum of its proper divisors (25219397945).

61111721671 is a wasteful number, since it uses less digits than its factorization.

61111721671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22013 (or 21991 counting only the distinct ones).

The product of its digits is 3528, while the sum is 34.

The spelling of 61111721671 in words is "sixty-one billion, one hundred eleven million, seven hundred twenty-one thousand, six hundred seventy-one".