661253040 has 180 divisors, whose sum is σ = 2583410544. Its totient is φ = 151135488.

The previous prime is 661252987. The next prime is 661253057. The reversal of 661253040 is 40352166.

661253040 is a `hidden beast` number, since 6 + 612 + 5 + 3 + 0 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (180).

It is a junction number, because it is equal to n+sod(n) for n = 661252995 and 661253013.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 25909 + ... + 44651.

Almost surely, 2^661253040 is an apocalyptic number.

661253040 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 661253040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1291705272).

661253040 is an abundant number, since it is smaller than the sum of its proper divisors (1922157504).

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

661253040 is a wasteful number, since it uses less digits than its factorization.

661253040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18776 (or 18760 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 661253040 is about 25714.8408511505. The cubic root of 661253040 is about 871.2094158711.

The spelling of 661253040 in words is "six hundred sixty-one million, two hundred fifty-three thousand, forty".