661521552 has 160 divisors (see below), whose sum is σ = 1848631680. Its totient is φ = 203427840.

The previous prime is 661521551. The next prime is 661521563. The reversal of 661521552 is 255125166.

It is a super-2 number, since 2×661521552² = 875221527520977408, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (661521551) 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, 3823738 + ... + 3823910.

It is an arithmetic number, because the mean of its divisors is an integer number (11553948).

Almost surely, 2^661521552 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 661521552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (924315840).

661521552 is an abundant number, since it is smaller than the sum of its proper divisors (1187110128).

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

661521552 is a wasteful number, since it uses less digits than its factorization.

661521552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321 (or 315 counting only the distinct ones).

The product of its digits is 18000, while the sum is 33.

The square root of 661521552 is about 25720.0612751992. The cubic root of 661521552 is about 871.3273225886.

The spelling of 661521552 in words is "six hundred sixty-one million, five hundred twenty-one thousand, five hundred fifty-two".