661145304 has 64 divisors (see below), whose sum is σ = 1771395840. Its totient is φ = 205096320.

The previous prime is 661145297. The next prime is 661145357. The reversal of 661145304 is 403541166.

It is a super-2 number, since 2×661145304² = 874226226002504832, 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 15 ways as a sum of consecutive naturals, for example, 4239 + ... + 36609.

It is an arithmetic number, because the mean of its divisors is an integer number (27678060).

Almost surely, 2^661145304 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 661145304, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (885697920).

661145304 is an abundant number, since it is smaller than the sum of its proper divisors (1110250536).

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

661145304 is a wasteful number, since it uses less digits than its factorization.

661145304 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32440 (or 32436 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 661145304 is about 25712.7459443755. The cubic root of 661145304 is about 871.1620987777.

It can be divided in two parts, 6611 and 45304, that added together give a palindrome (51915).

The spelling of 661145304 in words is "six hundred sixty-one million, one hundred forty-five thousand, three hundred four".