21054040 has 32 divisors (see below), whose sum is σ = 54139680. Its totient is φ = 7218432.

The previous prime is 21054037. The next prime is 21054049. The reversal of 21054040 is 4045012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21054049) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37317 + ... + 37876.

It is an arithmetic number, because the mean of its divisors is an integer number (1691865).

Almost surely, 2^21054040 is an apocalyptic number.

21054040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21054040 is an abundant number, since it is smaller than the sum of its proper divisors (33085640).

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

21054040 is a wasteful number, since it uses less digits than its factorization.

21054040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75211 (or 75207 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 21054040 is about 4588.4681539703. The cubic root of 21054040 is about 276.1288693159.

Adding to 21054040 its reverse (4045012), we get a palindrome (25099052).

Subtracting from 21054040 its reverse (4045012), we obtain a triangular number (17009028 = T₅₈₃₂).

The spelling of 21054040 in words is "twenty-one million, fifty-four thousand, forty".