61979909 has 4 divisors (see below), whose sum is σ = 65625804. Its totient is φ = 58334016.

The previous prime is 61979893. The next prime is 61979927. The reversal of 61979909 is 90997916.

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 30283009 + 31696900 = 5503^2 + 5630^2 .

It is a cyclic number.

It is not a de Polignac number, because 61979909 - 2⁴ = 61979893 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 (61979959) 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, 1822922 + ... + 1822955.

It is an arithmetic number, because the mean of its divisors is an integer number (16406451).

Almost surely, 2^61979909 is an apocalyptic number.

It is an amenable number.

61979909 is a deficient number, since it is larger than the sum of its proper divisors (3645895).

61979909 is a wasteful number, since it uses less digits than its factorization.

61979909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3645894.

The product of its (nonzero) digits is 275562, while the sum is 50.

The square root of 61979909 is about 7872.7319908657. The cubic root of 61979909 is about 395.7464047363.

The spelling of 61979909 in words is "sixty-one million, nine hundred seventy-nine thousand, nine hundred nine".