661421053040 has 40 divisors (see below), whose sum is σ = 1677604309488. Its totient is φ = 240516746240.

The previous prime is 661421053037. The next prime is 661421053081. The reversal of 661421053040 is 40350124166.

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 661421052988 and 661421053006.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 375806537 + ... + 375808296.

Almost surely, 2^661421053040 is an apocalyptic number.

It is an amenable number.

661421053040 is an abundant number, since it is smaller than the sum of its proper divisors (1016183256448).

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

661421053040 is a wasteful number, since it uses less digits than its factorization.

661421053040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 751614857 (or 751614851 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 32.

The spelling of 661421053040 in words is "six hundred sixty-one billion, four hundred twenty-one million, fifty-three thousand, forty".