21354140 has 12 divisors (see below), whose sum is σ = 44843736. Its totient is φ = 8541648.

The previous prime is 21354139. The next prime is 21354167. The reversal of 21354140 is 4145312.

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 1067707 = 21354140 / (2 + 1 + 3 + 5 + 4 + 1 + 4 + 0).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 533834 + ... + 533873.

It is an arithmetic number, because the mean of its divisors is an integer number (3736978).

Almost surely, 2^21354140 is an apocalyptic number.

21354140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21354140 is an abundant number, since it is smaller than the sum of its proper divisors (23489596).

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

21354140 is a wasteful number, since it uses less digits than its factorization.

21354140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1067716 (or 1067714 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 21354140 is about 4621.0539923269. The cubic root of 21354140 is about 277.4346462985.

Adding to 21354140 its reverse (4145312), we get a palindrome (25499452).

The spelling of 21354140 in words is "twenty-one million, three hundred fifty-four thousand, one hundred forty".