61039991 has 2 divisors, whose sum is σ = 61039992. Its totient is φ = 61039990.

The previous prime is 61039967. The next prime is 61040009. The reversal of 61039991 is 19993016.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 61039991 - 2²² = 56845687 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61039931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30519995 + 30519996.

It is an arithmetic number, because the mean of its divisors is an integer number (30519996).

Almost surely, 2^61039991 is an apocalyptic number.

61039991 is a deficient number, since it is larger than the sum of its proper divisors (1).

61039991 is an equidigital number, since it uses as much as digits as its factorization.

61039991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13122, while the sum is 38.

The square root of 61039991 is about 7812.8094178727. The cubic root of 61039991 is about 393.7357238126.

The spelling of 61039991 in words is "sixty-one million, thirty-nine thousand, nine hundred ninety-one".