81623653 has 2 divisors, whose sum is σ = 81623654. Its totient is φ = 81623652.

The previous prime is 81623627. The next prime is 81623671. The reversal of 81623653 is 35632618.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 76615009 + 5008644 = 8753^2 + 2238^2 .

It is a cyclic number.

It is not a de Polignac number, because 81623653 - 2⁹ = 81623141 is a prime.

It is a super-3 number, since 3×81623653³ (a number of 25 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81623683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40811826 + 40811827.

It is an arithmetic number, because the mean of its divisors is an integer number (40811827).

Almost surely, 2^81623653 is an apocalyptic number.

It is an amenable number.

81623653 is a deficient number, since it is larger than the sum of its proper divisors (1).

81623653 is an equidigital number, since it uses as much as digits as its factorization.

81623653 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25920, while the sum is 34.

The square root of 81623653 is about 9034.5809532042. The cubic root of 81623653 is about 433.7824817672.

The spelling of 81623653 in words is "eighty-one million, six hundred twenty-three thousand, six hundred fifty-three".