661572 has 72 divisors (see below), whose sum is σ = 1886976. Its totient is φ = 194304.

The previous prime is 661553. The next prime is 661603. The reversal of 661572 is 275166.

It is a super-2 number, since 2×661572² = 875355022368, 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 23 ways as a sum of consecutive naturals, for example, 14053 + ... + 14099.

It is an arithmetic number, because the mean of its divisors is an integer number (26208).

2⁶⁶¹⁵⁷² 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 661572, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (943488).

661572 is an abundant number, since it is smaller than the sum of its proper divisors (1225404).

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

661572 is a wasteful number, since it uses less digits than its factorization.

661572 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97 (or 92 counting only the distinct ones).

The product of its digits is 2520, while the sum is 27.

The square root of 661572 is about 813.3707641660. The cubic root of 661572 is about 87.1349471327.

The spelling of 661572 in words is "six hundred sixty-one thousand, five hundred seventy-two".