661556010 has 32 divisors (see below), whose sum is σ = 1589429952. Its totient is φ = 176226560.

The previous prime is 661556009. The next prime is 661556011. The reversal of 661556010 is 10655166.

It is an interprime number because it is at equal distance from previous prime (661556009) and next prime (661556011).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (661556011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18025 + ... + 40595.

It is an arithmetic number, because the mean of its divisors is an integer number (49669686).

Almost surely, 2^661556010 is an apocalyptic number.

661556010 is an abundant number, since it is smaller than the sum of its proper divisors (927873942).

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

661556010 is a wasteful number, since it uses less digits than its factorization.

661556010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23558.

The product of its (nonzero) digits is 5400, while the sum is 30.

The square root of 661556010 is about 25720.7311326875. The cubic root of 661556010 is about 871.3424511840.

The spelling of 661556010 in words is "six hundred sixty-one million, five hundred fifty-six thousand, ten".