81951933 has 8 divisors (see below), whose sum is σ = 124879168. Its totient is φ = 46829664.

The previous prime is 81951923. The next prime is 81951943. The reversal of 81951933 is 33915918.

It is an interprime number because it is at equal distance from previous prime (81951923) and next prime (81951943).

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

It is not a de Polignac number, because 81951933 - 2⁶ = 81951869 is a prime.

It is a super-2 number, since 2×81951933² = 13432238644872978, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81951891 and 81951900.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81951923) 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, 1951216 + ... + 1951257.

It is an arithmetic number, because the mean of its divisors is an integer number (15609896).

Almost surely, 2^81951933 is an apocalyptic number.

It is an amenable number.

81951933 is a deficient number, since it is larger than the sum of its proper divisors (42927235).

81951933 is a wasteful number, since it uses less digits than its factorization.

81951933 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3902483.

The product of its digits is 29160, while the sum is 39.

The square root of 81951933 is about 9052.7306930009. The cubic root of 81951933 is about 434.3632432889.

The spelling of 81951933 in words is "eighty-one million, nine hundred fifty-one thousand, nine hundred thirty-three".