661297487690 has 32 divisors (see below), whose sum is σ = 1363525228800. Its totient is φ = 226206929664.

The previous prime is 661297487687. The next prime is 661297487783. The reversal of 661297487690 is 96784792166.

It is a super-2 number, since 2×661297487690² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10878590 + ... + 10939209.

It is an arithmetic number, because the mean of its divisors is an integer number (42610163400).

Almost surely, 2^661297487690 is an apocalyptic number.

661297487690 is an abundant number, since it is smaller than the sum of its proper divisors (702227741110).

661297487690 is a wasteful number, since it uses less digits than its factorization.

661297487690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21818246.

The product of its (nonzero) digits is 54867456, while the sum is 65.

The spelling of 661297487690 in words is "six hundred sixty-one billion, two hundred ninety-seven million, four hundred eighty-seven thousand, six hundred ninety".