61323991 has 2 divisors, whose sum is σ = 61323992. Its totient is φ = 61323990.

The previous prime is 61323989. The next prime is 61324027. The reversal of 61323991 is 19932316.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 61323991 - 2¹ = 61323989 is a prime.

Together with 61323989, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61323901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30661995 + 30661996.

It is an arithmetic number, because the mean of its divisors is an integer number (30661996).

Almost surely, 2^61323991 is an apocalyptic number.

61323991 is a deficient number, since it is larger than the sum of its proper divisors (1).

61323991 is an equidigital number, since it uses as much as digits as its factorization.

61323991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8748, while the sum is 34.

The square root of 61323991 is about 7830.9636060960. The cubic root of 61323991 is about 394.3454222960.

The spelling of 61323991 in words is "sixty-one million, three hundred twenty-three thousand, nine hundred ninety-one".