61051721031 has 20 divisors (see below), whose sum is σ = 104229394192. Its totient is φ = 34886697408.

The previous prime is 61051721023. The next prime is 61051721033. The reversal of 61051721031 is 13012715016.

61051721031 is a `hidden beast` number, since 610 + 5 + 1 + 7 + 2 + 10 + 31 = 666.

It is not a de Polignac number, because 61051721031 - 2³ = 61051721023 is a prime.

It is a super-2 number, since 2×61051721031² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 61051720986 and 61051721004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61051721033) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 53836930 + ... + 53838063.

Almost surely, 2^61051721031 is an apocalyptic number.

61051721031 is a deficient number, since it is larger than the sum of its proper divisors (43177673161).

61051721031 is a wasteful number, since it uses less digits than its factorization.

61051721031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107675012 (or 107675003 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 27.

The spelling of 61051721031 in words is "sixty-one billion, fifty-one million, seven hundred twenty-one thousand, thirty-one".