661225140 has 96 divisors (see below), whose sum is σ = 2100994560. Its totient is φ = 172568448.

The previous prime is 661225111. The next prime is 661225151. The reversal of 661225140 is 41522166.

661225140 is a `hidden beast` number, since 6 + 612 + 2 + 5 + 1 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12354 + ... + 38406.

It is an arithmetic number, because the mean of its divisors is an integer number (21885360).

Almost surely, 2^661225140 is an apocalyptic number.

661225140 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661225140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1050497280).

661225140 is an abundant number, since it is smaller than the sum of its proper divisors (1439769420).

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

661225140 is a wasteful number, since it uses less digits than its factorization.

661225140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26118 (or 26110 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 661225140 is about 25714.2983571397. The cubic root of 661225140 is about 871.1971628288.

The spelling of 661225140 in words is "six hundred sixty-one million, two hundred twenty-five thousand, one hundred forty".