81179749 has 4 divisors (see below), whose sum is σ = 92776864. Its totient is φ = 69582636.

The previous prime is 81179741. The next prime is 81179789. The reversal of 81179749 is 94797118.

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 81179749 - 2³ = 81179741 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81179699 and 81179708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81179741) 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, 5798547 + ... + 5798560.

It is an arithmetic number, because the mean of its divisors is an integer number (23194216).

Almost surely, 2^81179749 is an apocalyptic number.

It is an amenable number.

81179749 is a deficient number, since it is larger than the sum of its proper divisors (11597115).

81179749 is a wasteful number, since it uses less digits than its factorization.

81179749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11597114.

The product of its digits is 127008, while the sum is 46.

The square root of 81179749 is about 9009.9805216216. The cubic root of 81179749 is about 432.9946876232.

The spelling of 81179749 in words is "eighty-one million, one hundred seventy-nine thousand, seven hundred forty-nine".