61985729 has 4 divisors (see below), whose sum is σ = 66753876. Its totient is φ = 57217584.

The previous prime is 61985719. The next prime is 61985761. The reversal of 61985729 is 92758916.

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 9394225 + 52591504 = 3065^2 + 7252^2 .

It is a cyclic number.

It is not a de Polignac number, because 61985729 - 2¹⁶ = 61920193 is a prime.

It is a super-2 number, since 2×61985729² = 7684461199322882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61985719) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2384054 + ... + 2384079.

It is an arithmetic number, because the mean of its divisors is an integer number (16688469).

Almost surely, 2^61985729 is an apocalyptic number.

It is an amenable number.

61985729 is a deficient number, since it is larger than the sum of its proper divisors (4768147).

61985729 is a wasteful number, since it uses less digits than its factorization.

61985729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4768146.

The product of its digits is 272160, while the sum is 47.

The square root of 61985729 is about 7873.1016124524. The cubic root of 61985729 is about 395.7587913952.

The spelling of 61985729 in words is "sixty-one million, nine hundred eighty-five thousand, seven hundred twenty-nine".