661611516 has 24 divisors (see below), whose sum is σ = 1550172624. Its totient is φ = 219621120.

The previous prime is 661611463. The next prime is 661611523. The reversal of 661611516 is 615116166.

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, 111495 + ... + 117278.

It is an arithmetic number, because the mean of its divisors is an integer number (64590526).

Almost surely, 2^661611516 is an apocalyptic number.

It is an amenable number.

661611516 is an abundant number, since it is smaller than the sum of its proper divisors (888561108).

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

661611516 is a wasteful number, since it uses less digits than its factorization.

661611516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 229021 (or 229019 counting only the distinct ones).

The product of its digits is 6480, while the sum is 33.

The square root of 661611516 is about 25721.8101229288. The cubic root of 661611516 is about 871.3668196833.

The spelling of 661611516 in words is "six hundred sixty-one million, six hundred eleven thousand, five hundred sixteen".