661612653 has 36 divisors (see below), whose sum is σ = 1041624948. Its totient is φ = 402278400.

The previous prime is 661612643. The next prime is 661612667. The reversal of 661612653 is 356216166.

It can be written as a sum of positive squares in 6 ways, for example, as 2304324 + 659308329 = 1518^2 + 25677^2 .

It is not a de Polignac number, because 661612653 - 2⁹ = 661612141 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661612603) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1100553 + ... + 1101153.

Almost surely, 2^661612653 is an apocalyptic number.

It is an amenable number.

661612653 is a deficient number, since it is larger than the sum of its proper divisors (380012295).

661612653 is a wasteful number, since it uses less digits than its factorization.

661612653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 814 (or 714 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 661612653 is about 25721.8322247852. The cubic root of 661612653 is about 871.3673188400.

The spelling of 661612653 in words is "six hundred sixty-one million, six hundred twelve thousand, six hundred fifty-three".