81804407 has 2 divisors, whose sum is σ = 81804408. Its totient is φ = 81804406.

The previous prime is 81804403. The next prime is 81804409. The reversal of 81804407 is 70440818.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81804407 - 2² = 81804403 is a prime.

It is a super-2 number, since 2×81804407² = 13383922009243298, which contains 22 as substring.

Together with 81804409, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81804403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40902203 + 40902204.

It is an arithmetic number, because the mean of its divisors is an integer number (40902204).

Almost surely, 2^81804407 is an apocalyptic number.

81804407 is a deficient number, since it is larger than the sum of its proper divisors (1).

81804407 is an equidigital number, since it uses as much as digits as its factorization.

81804407 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7168, while the sum is 32.

The square root of 81804407 is about 9044.5788735574. The cubic root of 81804407 is about 434.1024466684.

The spelling of 81804407 in words is "eighty-one million, eight hundred four thousand, four hundred seven".