21409398 has 24 divisors (see below), whose sum is σ = 46678008. Its totient is φ = 7091712.

The previous prime is 21409397. The next prime is 21409417. The reversal of 21409398 is 89390412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21409391) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 715 + ... + 6582.

It is an arithmetic number, because the mean of its divisors is an integer number (1944917).

Almost surely, 2^21409398 is an apocalyptic number.

21409398 is an abundant number, since it is smaller than the sum of its proper divisors (25268610).

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

21409398 is a wasteful number, since it uses less digits than its factorization.

21409398 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7468 (or 7465 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 21409398 is about 4627.0290684196. The cubic root of 21409398 is about 277.6737455883.

The spelling of 21409398 in words is "twenty-one million, four hundred nine thousand, three hundred ninety-eight".