812898781 has 4 divisors (see below), whose sum is σ = 813162364. Its totient is φ = 812635200.

The previous prime is 812898773. The next prime is 812898787. The reversal of 812898781 is 187898218.

It is a happy number.

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 386476281 + 426422500 = 19659^2 + 20650^2 .

It is a cyclic number.

It is not a de Polignac number, because 812898781 - 2³ = 812898773 is a prime.

It is a super-2 number, since 2×812898781² = 1321608856302571922, 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 (812898787) 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, 127110 + ... + 133351.

It is an arithmetic number, because the mean of its divisors is an integer number (203290591).

Almost surely, 2^812898781 is an apocalyptic number.

It is an amenable number.

812898781 is a deficient number, since it is larger than the sum of its proper divisors (263583).

812898781 is a wasteful number, since it uses less digits than its factorization.

812898781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 263582.

The product of its digits is 516096, while the sum is 52.

The square root of 812898781 is about 28511.3798508596. The cubic root of 812898781 is about 933.2804262385.

The spelling of 812898781 in words is "eight hundred twelve million, eight hundred ninety-eight thousand, seven hundred eighty-one".