69991 has 2 divisors, whose sum is σ = 69992. Its totient is φ = 69990.

The previous prime is 69959. The next prime is 69997. The reversal of 69991 is 19996.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 69991 - 2⁵ = 69959 is a prime.

It is an Ulam number.

It is a plaindrome in base 16.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (69997) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34995 + 34996.

It is an arithmetic number, because the mean of its divisors is an integer number (34996).

2⁶⁹⁹⁹¹ is an apocalyptic number.

69991 is a deficient number, since it is larger than the sum of its proper divisors (1).

69991 is an equidigital number, since it uses as much as digits as its factorization.

69991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4374, while the sum is 34.

The square root of 69991 is about 264.5581221584. The cubic root of 69991 is about 41.2110866573.

The spelling of 69991 in words is "sixty-nine thousand, nine hundred ninety-one".