661272464140 has 12 divisors (see below), whose sum is σ = 1388672174736. Its totient is φ = 264508985648.

The previous prime is 661272464137. The next prime is 661272464147. The reversal of 661272464140 is 41464272166.

661272464140 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (661272464147) 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, 16531811584 + ... + 16531811623.

It is an arithmetic number, because the mean of its divisors is an integer number (115722681228).

Almost surely, 2^661272464140 is an apocalyptic number.

It is an amenable number.

661272464140 is an abundant number, since it is smaller than the sum of its proper divisors (727399710596).

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

661272464140 is a wasteful number, since it uses less digits than its factorization.

661272464140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33063623216 (or 33063623214 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 43.

The spelling of 661272464140 in words is "six hundred sixty-one billion, two hundred seventy-two million, four hundred sixty-four thousand, one hundred forty".