81623767 has 2 divisors, whose sum is σ = 81623768. Its totient is φ = 81623766.

The previous prime is 81623747. The next prime is 81623779. The reversal of 81623767 is 76732618.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81623767 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81623747) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40811883 + 40811884.

It is an arithmetic number, because the mean of its divisors is an integer number (40811884).

Almost surely, 2^81623767 is an apocalyptic number.

81623767 is a deficient number, since it is larger than the sum of its proper divisors (1).

81623767 is an equidigital number, since it uses as much as digits as its factorization.

81623767 is an evil number, because the sum of its binary digits is even.

The product of its digits is 84672, while the sum is 40.

The square root of 81623767 is about 9034.5872622937. The cubic root of 81623767 is about 433.7826837151.

The spelling of 81623767 in words is "eighty-one million, six hundred twenty-three thousand, seven hundred sixty-seven".