61991279 has 8 divisors (see below), whose sum is σ = 73927680. Its totient is φ = 50825016.

The previous prime is 61991273. The next prime is 61991323. The reversal of 61991279 is 97219916.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 61991279 - 2²⁰ = 60942703 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61991273) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 192359 + ... + 192680.

It is an arithmetic number, because the mean of its divisors is an integer number (9240960).

Almost surely, 2^61991279 is an apocalyptic number.

61991279 is a deficient number, since it is larger than the sum of its proper divisors (11936401).

61991279 is a wasteful number, since it uses less digits than its factorization.

61991279 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 385069.

The product of its digits is 61236, while the sum is 44.

The square root of 61991279 is about 7873.4540704827. The cubic root of 61991279 is about 395.7706026932.

The spelling of 61991279 in words is "sixty-one million, nine hundred ninety-one thousand, two hundred seventy-nine".