81634907 has 2 divisors, whose sum is σ = 81634908. Its totient is φ = 81634906.

The previous prime is 81634879. The next prime is 81634921. The reversal of 81634907 is 70943618.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81634907 - 2²² = 77440603 is a prime.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is not a weakly prime, because it can be changed into another prime (81634957) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40817453 + 40817454.

It is an arithmetic number, because the mean of its divisors is an integer number (40817454).

Almost surely, 2^81634907 is an apocalyptic number.

81634907 is a deficient number, since it is larger than the sum of its proper divisors (1).

81634907 is an equidigital number, since it uses as much as digits as its factorization.

81634907 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36288, while the sum is 38.

The square root of 81634907 is about 9035.2037608457. The cubic root of 81634907 is about 433.8024170169.

The spelling of 81634907 in words is "eighty-one million, six hundred thirty-four thousand, nine hundred seven".