819863540 has 24 divisors (see below), whose sum is σ = 1722477960. Its totient is φ = 327799808.

The previous prime is 819863537. The next prime is 819863579. The reversal of 819863540 is 45368918.

It can be written as a sum of positive squares in 4 ways, for example, as 4418404 + 815445136 = 2102^2 + 28556^2 .

It is a junction number, because it is equal to n+sod(n) for n = 819863491 and 819863500.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44876 + ... + 60444.

It is an arithmetic number, because the mean of its divisors is an integer number (71769915).

Almost surely, 2^819863540 is an apocalyptic number.

It is an amenable number.

819863540 is an abundant number, since it is smaller than the sum of its proper divisors (902614420).

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

819863540 is a wasteful number, since it uses less digits than its factorization.

819863540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18211 (or 18209 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 44.

The square root of 819863540 is about 28633.2593324616. The cubic root of 819863540 is about 935.9382386136.

The spelling of 819863540 in words is "eight hundred nineteen million, eight hundred sixty-three thousand, five hundred forty".