661051157 has 4 divisors (see below), whose sum is σ = 711901260. Its totient is φ = 610201056.

The previous prime is 661051147. The next prime is 661051177. The reversal of 661051157 is 751150166.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 385690321 + 275360836 = 19639^2 + 16594^2 .

It is a cyclic number.

It is not a de Polignac number, because 661051157 - 2¹² = 661047061 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 (661051147) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 25425032 + ... + 25425057.

It is an arithmetic number, because the mean of its divisors is an integer number (177975315).

Almost surely, 2^661051157 is an apocalyptic number.

It is an amenable number.

661051157 is a deficient number, since it is larger than the sum of its proper divisors (50850103).

661051157 is a wasteful number, since it uses less digits than its factorization.

661051157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50850102.

The product of its (nonzero) digits is 6300, while the sum is 32.

The square root of 661051157 is about 25710.9151334603. The cubic root of 661051157 is about 871.1207456939.

Subtracting 661051157 from its reverse (751150166), we obtain a palindrome (90099009).

The spelling of 661051157 in words is "six hundred sixty-one million, fifty-one thousand, one hundred fifty-seven".