991148564961 has 36 divisors (see below), whose sum is σ = 1505617665552. Its totient is φ = 627955511904.

The previous prime is 991148564951. The next prime is 991148564969. The reversal of 991148564961 is 169465841199.

991148564961 is a `hidden beast` number, since 9 + 9 + 1 + 1 + 4 + 8 + 564 + 9 + 61 = 666.

991148564961 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 991148564961 - 2⁵ = 991148564929 is a prime.

It is not an unprimeable number, because it can be changed into a prime (991148564969) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 405591 + ... + 1465196.

It is an arithmetic number, because the mean of its divisors is an integer number (41822712932).

Almost surely, 2^991148564961 is an apocalyptic number.

It is an amenable number.

991148564961 is a deficient number, since it is larger than the sum of its proper divisors (514469100591).

991148564961 is a wasteful number, since it uses less digits than its factorization.

991148564961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1870910 (or 1870870 counting only the distinct ones).

The product of its digits is 16796160, while the sum is 63.

The spelling of 991148564961 in words is "nine hundred ninety-one billion, one hundred forty-eight million, five hundred sixty-four thousand, nine hundred sixty-one".