812137680 has 60 divisors (see below), whose sum is σ = 2727431460. Its totient is φ = 216569856.

The previous prime is 812137649. The next prime is 812137699. The reversal of 812137680 is 86731218.

It can be written as a sum of positive squares in 2 ways, for example, as 271854144 + 540283536 = 16488^2 + 23244^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a super-2 number, since 2×812137680² = 1319135222551564800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 563265 + ... + 564704.

It is an arithmetic number, because the mean of its divisors is an integer number (45457191).

Almost surely, 2^812137680 is an apocalyptic number.

812137680 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

812137680 is an abundant number, since it is smaller than the sum of its proper divisors (1915293780).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

812137680 is a wasteful number, since it uses less digits than its factorization.

812137680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1127988 (or 1127979 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 812137680 is about 28498.0294055571. The cubic root of 812137680 is about 932.9890646389.

Adding to 812137680 its reverse (86731218), we get a palindrome (898868898).

The spelling of 812137680 in words is "eight hundred twelve million, one hundred thirty-seven thousand, six hundred eighty".