61981669 has 4 divisors (see below), whose sum is σ = 62254944. Its totient is φ = 61708396.

The previous prime is 61981663. The next prime is 61981681. The reversal of 61981669 is 96618916.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 61981669 - 2⁵ = 61981637 is a prime.

It is a super-2 number, since 2×61981669² = 7683454584051122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61981663) 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, 136297 + ... + 136750.

It is an arithmetic number, because the mean of its divisors is an integer number (15563736).

Almost surely, 2^61981669 is an apocalyptic number.

It is an amenable number.

61981669 is a deficient number, since it is larger than the sum of its proper divisors (273275).

61981669 is a wasteful number, since it uses less digits than its factorization.

61981669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 273274.

The product of its digits is 139968, while the sum is 46.

The square root of 61981669 is about 7872.8437682962. The cubic root of 61981669 is about 395.7501506118.

The spelling of 61981669 in words is "sixty-one million, nine hundred eighty-one thousand, six hundred sixty-nine".