61691239 has 2 divisors, whose sum is σ = 61691240. Its totient is φ = 61691238.

The previous prime is 61691219. The next prime is 61691243. The reversal of 61691239 is 93219616.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 61691239 - 2²⁵ = 28136807 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 61691198 and 61691207.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61691219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30845619 + 30845620.

It is an arithmetic number, because the mean of its divisors is an integer number (30845620).

Almost surely, 2^61691239 is an apocalyptic number.

61691239 is a deficient number, since it is larger than the sum of its proper divisors (1).

61691239 is an equidigital number, since it uses as much as digits as its factorization.

61691239 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17496, while the sum is 37.

The square root of 61691239 is about 7854.3770599584. The cubic root of 61691239 is about 395.1310551617.

The spelling of 61691239 in words is "sixty-one million, six hundred ninety-one thousand, two hundred thirty-nine".