661131636900 has 144 divisors (see below), whose sum is σ = 2190526464000. Its totient is φ = 150812726400.

The previous prime is 661131636883. The next prime is 661131636901. The reversal of 661131636900 is 9636131166.

It is a super-2 number, since 2×661131636900² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (661131636901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 732445 + ... + 1363355.

Almost surely, 2^661131636900 is an apocalyptic number.

661131636900 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661131636900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1095263232000).

661131636900 is an abundant number, since it is smaller than the sum of its proper divisors (1529394827100).

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

661131636900 is a wasteful number, since it uses less digits than its factorization.

661131636900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 631434 (or 631427 counting only the distinct ones).

The product of its (nonzero) digits is 104976, while the sum is 42.

The spelling of 661131636900 in words is "six hundred sixty-one billion, one hundred thirty-one million, six hundred thirty-six thousand, nine hundred".