81154691 has 2 divisors, whose sum is σ = 81154692. Its totient is φ = 81154690.

The previous prime is 81154687. The next prime is 81154693. The reversal of 81154691 is 19645118.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81154691 - 2² = 81154687 is a prime.

Together with 81154693, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81154693) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40577345 + 40577346.

It is an arithmetic number, because the mean of its divisors is an integer number (40577346).

Almost surely, 2^81154691 is an apocalyptic number.

81154691 is a deficient number, since it is larger than the sum of its proper divisors (1).

81154691 is an equidigital number, since it uses as much as digits as its factorization.

81154691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8640, while the sum is 35.

The square root of 81154691 is about 9008.5898452533. The cubic root of 81154691 is about 432.9501317761.

The spelling of 81154691 in words is "eighty-one million, one hundred fifty-four thousand, six hundred ninety-one".