61447991631155 has 4 divisors (see below), whose sum is σ = 73737589957392. Its totient is φ = 49158393304920.

The previous prime is 61447991631149. The next prime is 61447991631179. The reversal of 61447991631155 is 55113619974416.

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

It is not a de Polignac number, because 61447991631155 - 2⁸ = 61447991630899 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6144799163111 + ... + 6144799163120.

It is an arithmetic number, because the mean of its divisors is an integer number (18434397489348).

Almost surely, 2^{61447991631155} is an apocalyptic number.

61447991631155 is a deficient number, since it is larger than the sum of its proper divisors (12289598326237).

61447991631155 is a wasteful number, since it uses less digits than its factorization.

61447991631155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12289598326236.

The product of its digits is 24494400, while the sum is 62.

The spelling of 61447991631155 in words is "sixty-one trillion, four hundred forty-seven billion, nine hundred ninety-one million, six hundred thirty-one thousand, one hundred fifty-five".