661565354 has 4 divisors (see below), whose sum is σ = 992348034. Its totient is φ = 330782676.

The previous prime is 661565341. The next prime is 661565417. The reversal of 661565354 is 453565166.

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

It can be written as a sum of positive squares in only one way, i.e., 620259025 + 41306329 = 24905^2 + 6427^2 .

It is a super-2 number, since 2×661565354² = 875337435226290632, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165391337 + ... + 165391340.

Almost surely, 2^661565354 is an apocalyptic number.

661565354 is a deficient number, since it is larger than the sum of its proper divisors (330782680).

661565354 is a wasteful number, since it uses less digits than its factorization.

661565354 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330782679.

The product of its digits is 324000, while the sum is 41.

The square root of 661565354 is about 25720.9127754052. The cubic root of 661565354 is about 871.3465535252.

The spelling of 661565354 in words is "six hundred sixty-one million, five hundred sixty-five thousand, three hundred fifty-four".