813861992449 has 9 divisors (see below), whose sum is σ = 894586486339. Its totient is φ = 739865517160.

The previous prime is 813861992431. The next prime is 813861992453. The reversal of 813861992449 is 944299168318.

The square root of 813861992449 is 902143.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 19847025 + 813842145424 = 4455^2 + 902132^2 .

It is not a de Polignac number, because 813861992449 - 2¹⁷ = 813861861377 is a prime.

It is a super-2 number, since 2×813861992449² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (813861092449) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 9882567 + ... + 9964579.

Almost surely, 2^813861992449 is an apocalyptic number.

813861992449 is the 902143-rd square number.

813861992449 is the 451072-nd centered octagonal number.

It is an amenable number.

813861992449 is a deficient number, since it is larger than the sum of its proper divisors (80724493890).

813861992449 is an frugal number, since it uses more digits than its factorization.

813861992449 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164048 (or 82024 counting only the distinct ones).

The product of its digits is 26873856, while the sum is 64.

Multiplying 813861992449 by its sum of digits (64), we get a square (52087167516736 = 7217144²).

The spelling of 813861992449 in words is "eight hundred thirteen billion, eight hundred sixty-one million, nine hundred ninety-two thousand, four hundred forty-nine".