125567721 has 6 divisors (see below), whose sum is σ = 181375610. Its totient is φ = 83711808.

The previous prime is 125567719. The next prime is 125567731. The reversal of 125567721 is 127765521.

125567721 is a `hidden beast` number, since 1 + 25 + 567 + 72 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 124545600 + 1022121 = 11160^2 + 1011^2 .

It is not a de Polignac number, because 125567721 - 2¹ = 125567719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (125567711) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6975976 + ... + 6975993.

Almost surely, 2^125567721 is an apocalyptic number.

It is an amenable number.

125567721 is a deficient number, since it is larger than the sum of its proper divisors (55807889).

125567721 is a wasteful number, since it uses less digits than its factorization.

125567721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13951975 (or 13951972 counting only the distinct ones).

The product of its digits is 29400, while the sum is 36.

The square root of 125567721 is about 11205.7003797175. The cubic root of 125567721 is about 500.7558182352.

The spelling of 125567721 in words is "one hundred twenty-five million, five hundred sixty-seven thousand, seven hundred twenty-one".