661151065 has 8 divisors (see below), whose sum is σ = 793527048. Its totient is φ = 528823680.

The previous prime is 661151059. The next prime is 661151081. The reversal of 661151065 is 560151166.

It can be written as a sum of positive squares in 4 ways, for example, as 22477081 + 638673984 = 4741^2 + 25272^2 .

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

It is not a de Polignac number, because 661151065 - 2¹⁹ = 660626777 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33135 + ... + 49195.

It is an arithmetic number, because the mean of its divisors is an integer number (99190881).

Almost surely, 2^661151065 is an apocalyptic number.

It is an amenable number.

661151065 is a deficient number, since it is larger than the sum of its proper divisors (132375983).

661151065 is a wasteful number, since it uses less digits than its factorization.

661151065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24299.

The product of its (nonzero) digits is 5400, while the sum is 31.

The square root of 661151065 is about 25712.8579702841. The cubic root of 661151065 is about 871.1646291092.

The spelling of 661151065 in words is "six hundred sixty-one million, one hundred fifty-one thousand, sixty-five".