251566610061 has 16 divisors (see below), whose sum is σ = 366311514240. Its totient is φ = 152629794240.

The previous prime is 251566610027. The next prime is 251566610063. The reversal of 251566610061 is 160016665152.

251566610061 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 251566610061 - 2⁷ = 251566609933 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251566610063) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45422766 + ... + 45428303.

It is an arithmetic number, because the mean of its divisors is an integer number (22894469640).

Almost surely, 2^251566610061 is an apocalyptic number.

It is an amenable number.

251566610061 is a deficient number, since it is larger than the sum of its proper divisors (114744904179).

251566610061 is a wasteful number, since it uses less digits than its factorization.

251566610061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90851156.

The product of its (nonzero) digits is 64800, while the sum is 39.

The spelling of 251566610061 in words is "two hundred fifty-one billion, five hundred sixty-six million, six hundred ten thousand, sixty-one".