661501375 has 16 divisors (see below), whose sum is σ = 829775232. Its totient is φ = 526495200.

The previous prime is 661501369. The next prime is 661501387. The reversal of 661501375 is 573105166.

It is not a de Polignac number, because 661501375 - 2¹⁹ = 660977087 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 661501375.

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, 11194 + ... + 38056.

It is an arithmetic number, because the mean of its divisors is an integer number (51860952).

Almost surely, 2^661501375 is an apocalyptic number.

661501375 is a deficient number, since it is larger than the sum of its proper divisors (168273857).

661501375 is a wasteful number, since it uses less digits than its factorization.

661501375 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27075 (or 27065 counting only the distinct ones).

The product of its (nonzero) digits is 18900, while the sum is 34.

The square root of 661501375 is about 25719.6690297523. The cubic root of 661501375 is about 871.3184637439.

The spelling of 661501375 in words is "six hundred sixty-one million, five hundred one thousand, three hundred seventy-five".