8154812821 has 4 divisors (see below), whose sum is σ = 8235553644. Its totient is φ = 8074072000.

The previous prime is 8154812803. The next prime is 8154812843. The reversal of 8154812821 is 1282184518.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7976990596 + 177822225 = 89314^2 + 13335^2 .

It is a cyclic number.

It is not a de Polignac number, because 8154812821 - 2³¹ = 6007329173 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8154812801) 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, 40370260 + ... + 40370461.

It is an arithmetic number, because the mean of its divisors is an integer number (2058888411).

Almost surely, 2^8154812821 is an apocalyptic number.

It is an amenable number.

8154812821 is a deficient number, since it is larger than the sum of its proper divisors (80740823).

8154812821 is a wasteful number, since it uses less digits than its factorization.

8154812821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80740822.

The product of its digits is 40960, while the sum is 40.

The square root of 8154812821 is about 90304.0022424256. The cubic root of 8154812821 is about 2012.8187329286.

It can be divided in two parts, 815 and 4812821, that added together give a square (4813636 = 2194²).

The spelling of 8154812821 in words is "eight billion, one hundred fifty-four million, eight hundred twelve thousand, eight hundred twenty-one".