21840054 has 16 divisors (see below), whose sum is σ = 44610048. Its totient is φ = 7125032.

The previous prime is 21840047. The next prime is 21840061. The reversal of 21840054 is 45004812.

It is an interprime number because it is at equal distance from previous prime (21840047) and next prime (21840061).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38442 + ... + 39005.

It is an arithmetic number, because the mean of its divisors is an integer number (2788128).

Almost surely, 2^21840054 is an apocalyptic number.

21840054 is an abundant number, since it is smaller than the sum of its proper divisors (22769994).

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

21840054 is a wasteful number, since it uses less digits than its factorization.

21840054 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77499.

The product of its (nonzero) digits is 1280, while the sum is 24.

The square root of 21840054 is about 4673.3343556822. The cubic root of 21840054 is about 279.5232277486.

Adding to 21840054 its reverse (45004812), we get a palindrome (66844866).

The spelling of 21840054 in words is "twenty-one million, eight hundred forty thousand, fifty-four".