661511759 has 8 divisors (see below), whose sum is σ = 683275392. Its totient is φ = 639774720.

The previous prime is 661511737. The next prime is 661511777. The reversal of 661511759 is 957115166.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 661511759 - 2⁸ = 661511503 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661511659) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52367 + ... + 63759.

It is an arithmetic number, because the mean of its divisors is an integer number (85409424).

Almost surely, 2^661511759 is an apocalyptic number.

661511759 is a deficient number, since it is larger than the sum of its proper divisors (21763633).

661511759 is a wasteful number, since it uses less digits than its factorization.

661511759 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13297.

The product of its digits is 56700, while the sum is 41.

The square root of 661511759 is about 25719.8708978097. The cubic root of 661511759 is about 871.3230229300.

The spelling of 661511759 in words is "six hundred sixty-one million, five hundred eleven thousand, seven hundred fifty-nine".