661151005 has 4 divisors (see below), whose sum is σ = 793381212. Its totient is φ = 528920800.

The previous prime is 661151003. The next prime is 661151009. The reversal of 661151005 is 500151166.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 500151166 = 2 ⋅250075583.

It can be written as a sum of positive squares in 2 ways, for example, as 445589881 + 215561124 = 21109^2 + 14682^2 .

It is not a de Polignac number, because 661151005 - 2¹ = 661151003 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 (661151003) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66115096 + ... + 66115105.

It is an arithmetic number, because the mean of its divisors is an integer number (198345303).

Almost surely, 2^661151005 is an apocalyptic number.

It is an amenable number.

661151005 is a deficient number, since it is larger than the sum of its proper divisors (132230207).

661151005 is a wasteful number, since it uses less digits than its factorization.

661151005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132230206.

The product of its (nonzero) digits is 900, while the sum is 25.

The square root of 661151005 is about 25712.8568035526. The cubic root of 661151005 is about 871.1646027562.

The spelling of 661151005 in words is "six hundred sixty-one million, one hundred fifty-one thousand, five".