21854540 has 24 divisors (see below), whose sum is σ = 46344480. Its totient is φ = 8656944.

The previous prime is 21854533. The next prime is 21854543. The reversal of 21854540 is 4545812.

It is a super-2 number, since 2×21854540² = 955241837223200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21854543) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 212129 + ... + 212231.

It is an arithmetic number, because the mean of its divisors is an integer number (1931020).

Almost surely, 2^21854540 is an apocalyptic number.

21854540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21854540 is an abundant number, since it is smaller than the sum of its proper divisors (24489940).

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

21854540 is an frugal number, since it uses more digits than its factorization.

21854540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 318 (or 110 counting only the distinct ones).

The product of its (nonzero) digits is 6400, while the sum is 29.

The square root of 21854540 is about 4674.8839557790. The cubic root of 21854540 is about 279.5850145093.

The spelling of 21854540 in words is "twenty-one million, eight hundred fifty-four thousand, five hundred forty".