21159402 has 64 divisors (see below), whose sum is σ = 49268736. Its totient is φ = 5994560.

The previous prime is 21159389. The next prime is 21159427. The reversal of 21159402 is 20495112.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 80323 + ... + 80585.

It is an arithmetic number, because the mean of its divisors is an integer number (769824).

Almost surely, 2^21159402 is an apocalyptic number.

21159402 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21159402, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24634368).

21159402 is an abundant number, since it is smaller than the sum of its proper divisors (28109334).

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

21159402 is a wasteful number, since it uses less digits than its factorization.

21159402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 355.

The product of its (nonzero) digits is 720, while the sum is 24.

The square root of 21159402 is about 4599.9349995408. The cubic root of 21159402 is about 276.5887191906.

The spelling of 21159402 in words is "twenty-one million, one hundred fifty-nine thousand, four hundred two".