81601623 has 12 divisors (see below), whose sum is σ = 118307488. Its totient is φ = 54198720.

The previous prime is 81601601. The next prime is 81601627. The reversal of 81601623 is 32610618.

It is not a de Polignac number, because 81601623 - 2¹⁴ = 81585239 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81601627) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14290 + ... + 19167.

Almost surely, 2^81601623 is an apocalyptic number.

81601623 is a deficient number, since it is larger than the sum of its proper divisors (36705865).

81601623 is a wasteful number, since it uses less digits than its factorization.

81601623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33734 (or 33731 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 81601623 is about 9033.3616666222. The cubic root of 81601623 is about 433.7434526885.

The spelling of 81601623 in words is "eighty-one million, six hundred one thousand, six hundred twenty-three".