661057097 has 4 divisors (see below), whose sum is σ = 662279556. Its totient is φ = 659834640.

The previous prime is 661057093. The next prime is 661057141. The reversal of 661057097 is 790750166.

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 143904016 + 517153081 = 11996^2 + 22741^2 .

It is a cyclic number.

It is not a de Polignac number, because 661057097 - 2² = 661057093 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661057091) 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, 610418 + ... + 611499.

It is an arithmetic number, because the mean of its divisors is an integer number (165569889).

Almost surely, 2^661057097 is an apocalyptic number.

It is an amenable number.

661057097 is a deficient number, since it is larger than the sum of its proper divisors (1222459).

661057097 is a wasteful number, since it uses less digits than its factorization.

661057097 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1222458.

The product of its (nonzero) digits is 79380, while the sum is 41.

The square root of 661057097 is about 25711.0306483424. The cubic root of 661057097 is about 871.1233548928.

The spelling of 661057097 in words is "six hundred sixty-one million, fifty-seven thousand, ninety-seven".