661644030 has 64 divisors (see below), whose sum is σ = 1695168000. Its totient is φ = 164787840.

The previous prime is 661644007. The next prime is 661644037. The reversal of 661644030 is 30446166.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661644037) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 32296 + ... + 48644.

It is an arithmetic number, because the mean of its divisors is an integer number (26487000).

Almost surely, 2^661644030 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661644030, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (847584000).

661644030 is an abundant number, since it is smaller than the sum of its proper divisors (1033523970).

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

661644030 is a wasteful number, since it uses less digits than its factorization.

661644030 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16449.

The product of its (nonzero) digits is 10368, while the sum is 30.

The square root of 661644030 is about 25722.4421468880. The cubic root of 661644030 is about 871.3810934960.

The spelling of 661644030 in words is "six hundred sixty-one million, six hundred forty-four thousand, thirty".