21354040 has 64 divisors (see below), whose sum is σ = 52565760. Its totient is φ = 7772160.

The previous prime is 21354019. The next prime is 21354049. The reversal of 21354040 is 4045312.

It is a junction number, because it is equal to n+sod(n) for n = 21353999 and 21354017.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21354049) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20574 + ... + 21586.

It is an arithmetic number, because the mean of its divisors is an integer number (821340).

Almost surely, 2^21354040 is an apocalyptic number.

21354040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21354040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26282880).

21354040 is an abundant number, since it is smaller than the sum of its proper divisors (31211720).

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

21354040 is a wasteful number, since it uses less digits than its factorization.

21354040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1072 (or 1068 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 21354040 is about 4621.0431722718. The cubic root of 21354040 is about 277.4342132286.

Adding to 21354040 its reverse (4045312), we get a palindrome (25399352).

It can be divided in two parts, 21 and 354040, that added together give a triangular number (354061 = T₈₄₁).

The spelling of 21354040 in words is "twenty-one million, three hundred fifty-four thousand, forty".