21402048 has 112 divisors (see below), whose sum is σ = 61447680. Its totient is φ = 6549504.

The previous prime is 21402047. The next prime is 21402049. The reversal of 21402048 is 84020412.

Added to its reverse (84020412) it gives a triangular number (105422460 = T₁₄₅₂₀).

It is an interprime number because it is at equal distance from previous prime (21402047) and next prime (21402049).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21402047) 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, 257815 + ... + 257897.

It is an arithmetic number, because the mean of its divisors is an integer number (548640).

Almost surely, 2^21402048 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21402048, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30723840).

21402048 is an abundant number, since it is smaller than the sum of its proper divisors (40045632).

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

21402048 is a wasteful number, since it uses less digits than its factorization.

21402048 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 194 (or 184 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 21.

The square root of 21402048 is about 4626.2347540954. The cubic root of 21402048 is about 277.6419661547.

Adding to 21402048 its reverse (84020412), we get a triangular number (105422460 = T₁₄₅₂₀).

The spelling of 21402048 in words is "twenty-one million, four hundred two thousand, forty-eight".