804157981 has 4 divisors (see below), whose sum is σ = 877263264. Its totient is φ = 731052700.

The previous prime is 804157979. The next prime is 804158009. The reversal of 804157981 is 189751408.

It is a happy number.

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 804157981 - 2¹ = 804157979 is a prime.

It is a super-2 number, since 2×804157981² = 1293340116811992722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (804157481) 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, 36552625 + ... + 36552646.

It is an arithmetic number, because the mean of its divisors is an integer number (219315816).

Almost surely, 2^804157981 is an apocalyptic number.

It is an amenable number.

804157981 is a deficient number, since it is larger than the sum of its proper divisors (73105283).

804157981 is a wasteful number, since it uses less digits than its factorization.

804157981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73105282.

The product of its (nonzero) digits is 80640, while the sum is 43.

The square root of 804157981 is about 28357.6794008254. The cubic root of 804157981 is about 929.9232915495.

The spelling of 804157981 in words is "eight hundred four million, one hundred fifty-seven thousand, nine hundred eighty-one".