61990367729 has 4 divisors (see below), whose sum is σ = 61991845860. Its totient is φ = 61988889600.

The previous prime is 61990367653. The next prime is 61990367759. The reversal of 61990367729 is 92776309916.

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 42739360225 + 19251007504 = 206735^2 + 138748^2 .

It is a cyclic number.

It is not a de Polignac number, because 61990367729 - 2¹⁶ = 61990302193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61990367759) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 674264 + ... + 760665.

It is an arithmetic number, because the mean of its divisors is an integer number (15497961465).

Almost surely, 2^61990367729 is an apocalyptic number.

It is an amenable number.

61990367729 is a deficient number, since it is larger than the sum of its proper divisors (1478131).

61990367729 is a wasteful number, since it uses less digits than its factorization.

61990367729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1478130.

The product of its (nonzero) digits is 7715736, while the sum is 59.

The spelling of 61990367729 in words is "sixty-one billion, nine hundred ninety million, three hundred sixty-seven thousand, seven hundred twenty-nine".