81919262 has 4 divisors (see below), whose sum is σ = 122878896. Its totient is φ = 40959630.

The previous prime is 81919259. The next prime is 81919289. The reversal of 81919262 is 26291918.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20479814 + ... + 20479817.

It is an arithmetic number, because the mean of its divisors is an integer number (30719724).

Almost surely, 2^81919262 is an apocalyptic number.

81919262 is a deficient number, since it is larger than the sum of its proper divisors (40959634).

81919262 is a wasteful number, since it uses less digits than its factorization.

81919262 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40959633.

The product of its digits is 15552, while the sum is 38.

The square root of 81919262 is about 9050.9260299706. The cubic root of 81919262 is about 434.3055144584.

The spelling of 81919262 in words is "eighty-one million, nine hundred nineteen thousand, two hundred sixty-two".