661401500490 has 64 divisors (see below), whose sum is σ = 1781920264320. Its totient is φ = 174555440640.

The previous prime is 661401500483. The next prime is 661401500581. The reversal of 661401500490 is 94005104166.

661401500490 is a `hidden beast` number, since 6 + 6 + 14 + 0 + 150 + 0 + 490 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12600796 + ... + 12653175.

It is an arithmetic number, because the mean of its divisors is an integer number (27842504130).

Almost surely, 2^661401500490 is an apocalyptic number.

661401500490 is an abundant number, since it is smaller than the sum of its proper divisors (1120518763830).

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

661401500490 is a wasteful number, since it uses less digits than its factorization.

661401500490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25254084 (or 25254078 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The spelling of 661401500490 in words is "six hundred sixty-one billion, four hundred one million, five hundred thousand, four hundred ninety".