540821391 has 32 divisors (see below), whose sum is σ = 834624000. Its totient is φ = 307860480.

The previous prime is 540821383. The next prime is 540821399. The reversal of 540821391 is 193128045.

It is an interprime number because it is at equal distance from previous prime (540821383) and next prime (540821399).

It is not a de Polignac number, because 540821391 - 2³ = 540821383 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (540821399) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 515035 + ... + 516083.

It is an arithmetic number, because the mean of its divisors is an integer number (26082000).

Almost surely, 2^540821391 is an apocalyptic number.

540821391 is a gapful number since it is divisible by the number (51) formed by its first and last digit.

540821391 is a deficient number, since it is larger than the sum of its proper divisors (293802609).

540821391 is a wasteful number, since it uses less digits than its factorization.

540821391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1999.

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 540821391 is about 23255.5668819317. The cubic root of 540821391 is about 814.7379643634.

The spelling of 540821391 in words is "five hundred forty million, eight hundred twenty-one thousand, three hundred ninety-one".