81751769 has 4 divisors (see below), whose sum is σ = 89183760. Its totient is φ = 74319780.

The previous prime is 81751711. The next prime is 81751777. The reversal of 81751769 is 96715718.

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 81751769 - 2²⁰ = 80703193 is a prime.

It is a super-2 number, since 2×81751769² = 13366703469258722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81751799) 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, 3715979 + ... + 3716000.

It is an arithmetic number, because the mean of its divisors is an integer number (22295940).

Almost surely, 2^81751769 is an apocalyptic number.

It is an amenable number.

81751769 is a deficient number, since it is larger than the sum of its proper divisors (7431991).

81751769 is a wasteful number, since it uses less digits than its factorization.

81751769 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7431990.

The product of its digits is 105840, while the sum is 44.

The square root of 81751769 is about 9041.6684854069. The cubic root of 81751769 is about 434.0093172626.

The spelling of 81751769 in words is "eighty-one million, seven hundred fifty-one thousand, seven hundred sixty-nine".