661634726274200 has 144 divisors (see below), whose sum is σ = 1831067040737880. Its totient is φ = 221570698890240.

The previous prime is 661634726274173. The next prime is 661634726274209. The reversal of 661634726274200 is 2472627436166.

It is a super-2 number, since 2×661634726274200² (a number of 30 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (56).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661634726274209) 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, 784622177 + ... + 785464976.

Almost surely, 2^{661634726274200} is an apocalyptic number.

It is an amenable number.

661634726274200 is an abundant number, since it is smaller than the sum of its proper divisors (1169432314463680).

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

661634726274200 is a wasteful number, since it uses less digits than its factorization.

661634726274200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1570087226 (or 1570087210 counting only the distinct ones).

The product of its (nonzero) digits is 24385536, while the sum is 56.

The spelling of 661634726274200 in words is "six hundred sixty-one trillion, six hundred thirty-four billion, seven hundred twenty-six million, two hundred seventy-four thousand, two hundred".