661995136 has 32 divisors (see below), whose sum is σ = 1438714080. Its totient is φ = 300906240.

The previous prime is 661995133. The next prime is 661995161. The reversal of 661995136 is 631599166.

661995136 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (32).

It is a super-3 number, since 3×661995136³ (a number of 27 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (661995133) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 233676 + ... + 236491.

It is an arithmetic number, because the mean of its divisors is an integer number (44959815).

Almost surely, 2^661995136 is an apocalyptic number.

It is an amenable number.

661995136 is an abundant number, since it is smaller than the sum of its proper divisors (776718944).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661995136 is a wasteful number, since it uses less digits than its factorization.

661995136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 470192 (or 470180 counting only the distinct ones).

The product of its digits is 262440, while the sum is 46.

The square root of 661995136 is about 25729.2661379994. The cubic root of 661995136 is about 871.5352010497.

The spelling of 661995136 in words is "six hundred sixty-one million, nine hundred ninety-five thousand, one hundred thirty-six".