61715956251 has 4 divisors (see below), whose sum is σ = 82287941672. Its totient is φ = 41143970832.

The previous prime is 61715956243. The next prime is 61715956277. The reversal of 61715956251 is 15265951716.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 61715956251 - 2³ = 61715956243 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 61715956251.

It is not an unprimeable number, because it can be changed into a prime (61715956231) 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 3 ways as a sum of consecutive naturals, for example, 10285992706 + ... + 10285992711.

It is an arithmetic number, because the mean of its divisors is an integer number (20571985418).

Almost surely, 2^61715956251 is an apocalyptic number.

61715956251 is a deficient number, since it is larger than the sum of its proper divisors (20571985421).

61715956251 is a wasteful number, since it uses less digits than its factorization.

61715956251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20571985420.

The product of its digits is 567000, while the sum is 48.

The spelling of 61715956251 in words is "sixty-one billion, seven hundred fifteen million, nine hundred fifty-six thousand, two hundred fifty-one".