661020460 has 48 divisors (see below), whose sum is σ = 1451520000. Its totient is φ = 252384704.

The previous prime is 661020449. The next prime is 661020487. The reversal of 661020460 is 64020166.

It is a happy number.

It is a super-2 number, since 2×661020460² = 873896097077223200, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 274341 + ... + 276739.

It is an arithmetic number, because the mean of its divisors is an integer number (30240000).

Almost surely, 2^661020460 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 661020460, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (725760000).

661020460 is an abundant number, since it is smaller than the sum of its proper divisors (790499540).

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

661020460 is a wasteful number, since it uses less digits than its factorization.

661020460 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3030 (or 3028 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 661020460 is about 25710.3181621698. The cubic root of 661020460 is about 871.1072615093.

The spelling of 661020460 in words is "six hundred sixty-one million, twenty thousand, four hundred sixty".