21598416 has 90 divisors (see below), whose sum is σ = 70337202. Its totient is φ = 6168960.

The previous prime is 21598411. The next prime is 21598433. The reversal of 21598416 is 61489512.

21598416 is a `hidden beast` number, since 21 + 598 + 41 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 21344400 + 254016 = 4620^2 + 504^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21598411) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 5526 + ... + 8586.

Almost surely, 2^21598416 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 21598416, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35168601).

21598416 is an abundant number, since it is smaller than the sum of its proper divisors (48738786).

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

21598416 is a wasteful number, since it uses less digits than its factorization.

21598416 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3089 (or 3073 counting only the distinct ones).

The product of its digits is 17280, while the sum is 36.

The square root of 21598416 is about 4647.4096010573. The cubic root of 21598416 is about 278.4885221867.

It can be divided in two parts, 215984 and 16, that added together give a cube (216000 = 60³).

The spelling of 21598416 in words is "twenty-one million, five hundred ninety-eight thousand, four hundred sixteen".