81919983 has 8 divisors (see below), whose sum is σ = 112993200. Its totient is φ = 52730048.

The previous prime is 81919973. The next prime is 81919993. The reversal of 81919983 is 38991918.

It is an interprime number because it is at equal distance from previous prime (81919973) and next prime (81919993).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81919983 - 2⁴ = 81919967 is a prime.

It is a super-2 number, since 2×81919983² = 13421767229440578, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81919973) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 470718 + ... + 470891.

It is an arithmetic number, because the mean of its divisors is an integer number (14124150).

Almost surely, 2^81919983 is an apocalyptic number.

81919983 is a deficient number, since it is larger than the sum of its proper divisors (31073217).

81919983 is a wasteful number, since it uses less digits than its factorization.

81919983 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 941641.

The product of its digits is 139968, while the sum is 48.

The square root of 81919983 is about 9050.9658600616. The cubic root of 81919983 is about 434.3067886128.

It can be divided in two parts, 819 and 19983, that added together give a palindrome (20802).

The spelling of 81919983 in words is "eighty-one million, nine hundred nineteen thousand, nine hundred eighty-three".