61317720 has 48 divisors (see below), whose sum is σ = 199283760. Its totient is φ = 16351296.

The previous prime is 61317653. The next prime is 61317733. The reversal of 61317720 is 2771316.

61317720 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 84804 + ... + 85523.

It is an arithmetic number, because the mean of its divisors is an integer number (4151745).

Almost surely, 2^61317720 is an apocalyptic number.

61317720 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

61317720 is an abundant number, since it is smaller than the sum of its proper divisors (137966040).

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

61317720 is a wasteful number, since it uses less digits than its factorization.

61317720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170344 (or 170337 counting only the distinct ones).

The product of its (nonzero) digits is 1764, while the sum is 27.

The square root of 61317720 is about 7830.5631981359. The cubic root of 61317720 is about 394.3319798982.

The spelling of 61317720 in words is "sixty-one million, three hundred seventeen thousand, seven hundred twenty".