81924371 has 4 divisors (see below), whose sum is σ = 86236200. Its totient is φ = 77612544.

The previous prime is 81924361. The next prime is 81924373. The reversal of 81924371 is 17342918.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81924371 - 2¹⁸ = 81662227 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81924373) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2155886 + ... + 2155923.

It is an arithmetic number, because the mean of its divisors is an integer number (21559050).

Almost surely, 2^81924371 is an apocalyptic number.

81924371 is a deficient number, since it is larger than the sum of its proper divisors (4311829).

81924371 is a wasteful number, since it uses less digits than its factorization.

81924371 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4311828.

The product of its digits is 12096, while the sum is 35.

The square root of 81924371 is about 9051.2082618842. The cubic root of 81924371 is about 434.3145429445.

The spelling of 81924371 in words is "eighty-one million, nine hundred twenty-four thousand, three hundred seventy-one".