81654431 has 2 divisors, whose sum is σ = 81654432. Its totient is φ = 81654430.

The previous prime is 81654389. The next prime is 81654437. The reversal of 81654431 is 13445618.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81654431 - 2¹⁸ = 81392287 is a prime.

It is a super-2 number, since 2×81654431² = 13334892203867522, which contains 22 as substring.

It is equal to p_4760438 and since 81654431 and 4760438 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81654437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40827215 + 40827216.

It is an arithmetic number, because the mean of its divisors is an integer number (40827216).

Almost surely, 2^81654431 is an apocalyptic number.

81654431 is a deficient number, since it is larger than the sum of its proper divisors (1).

81654431 is an equidigital number, since it uses as much as digits as its factorization.

81654431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11520, while the sum is 32.

The square root of 81654431 is about 9036.2841367456. The cubic root of 81654431 is about 433.8369973355.

The spelling of 81654431 in words is "eighty-one million, six hundred fifty-four thousand, four hundred thirty-one".