61779918 has 16 divisors (see below), whose sum is σ = 127820880. Its totient is φ = 19883136.

The previous prime is 61779917. The next prime is 61779937. The reversal of 61779918 is 81997716.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61779911) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 177355 + ... + 177702.

It is an arithmetic number, because the mean of its divisors is an integer number (7988805).

Almost surely, 2^61779918 is an apocalyptic number.

61779918 is an abundant number, since it is smaller than the sum of its proper divisors (66040962).

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

61779918 is a wasteful number, since it uses less digits than its factorization.

61779918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 355091.

The product of its digits is 190512, while the sum is 48.

The square root of 61779918 is about 7860.0202289816. The cubic root of 61779918 is about 395.3202935436.

The spelling of 61779918 in words is "sixty-one million, seven hundred seventy-nine thousand, nine hundred eighteen".