661464860 has 96 divisors (see below), whose sum is σ = 1684032000. Its totient is φ = 213186816.

The previous prime is 661464833. The next prime is 661464877. The reversal of 661464860 is 68464166.

It is a super-2 number, since 2×661464860² = 875071522029639200, which contains 22 as substring.

It is a congruent number.

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, 368846 + ... + 370634.

It is an arithmetic number, because the mean of its divisors is an integer number (17542000).

Almost surely, 2^661464860 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661464860, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (842016000).

661464860 is an abundant number, since it is smaller than the sum of its proper divisors (1022567140).

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

661464860 is a wasteful number, since it uses less digits than its factorization.

661464860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1963 (or 1961 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 41.

The square root of 661464860 is about 25718.9591546781. The cubic root of 661464860 is about 871.3024311347.

The spelling of 661464860 in words is "six hundred sixty-one million, four hundred sixty-four thousand, eight hundred sixty".