81750381 has 4 divisors (see below), whose sum is σ = 109000512. Its totient is φ = 54500252.

The previous prime is 81750373. The next prime is 81750401. The reversal of 81750381 is 18305718.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81750381 - 2³ = 81750373 is a prime.

It is a super-2 number, since 2×81750381² = 13366249587290322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81750311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13625061 + ... + 13625066.

It is an arithmetic number, because the mean of its divisors is an integer number (27250128).

Almost surely, 2^81750381 is an apocalyptic number.

It is an amenable number.

81750381 is a deficient number, since it is larger than the sum of its proper divisors (27250131).

81750381 is a wasteful number, since it uses less digits than its factorization.

81750381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27250130.

The product of its (nonzero) digits is 6720, while the sum is 33.

The square root of 81750381 is about 9041.5917293362. The cubic root of 81750381 is about 434.0068610127.

The spelling of 81750381 in words is "eighty-one million, seven hundred fifty thousand, three hundred eighty-one".