61809564 has 24 divisors (see below), whose sum is σ = 145711888. Its totient is φ = 20390400.

The previous prime is 61809563. The next prime is 61809581. The reversal of 61809564 is 46590816.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61809563) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25387 + ... + 27714.

Almost surely, 2^61809564 is an apocalyptic number.

It is an amenable number.

61809564 is an abundant number, since it is smaller than the sum of its proper divisors (83902324).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

61809564 is a wasteful number, since it uses less digits than its factorization.

61809564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53205 (or 53203 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 39.

The square root of 61809564 is about 7861.9058758039. The cubic root of 61809564 is about 395.3835168459.

The spelling of 61809564 in words is "sixty-one million, eight hundred nine thousand, five hundred sixty-four".