21065898 has 32 divisors (see below), whose sum is σ = 48738816. Its totient is φ = 5945328.

The previous prime is 21065897. The next prime is 21065899. The reversal of 21065898 is 89856012.

It is an interprime number because it is at equal distance from previous prime (21065897) and next prime (21065899).

It is not an unprimeable number, because it can be changed into a prime (21065893) 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, 465 + ... + 6507.

It is an arithmetic number, because the mean of its divisors is an integer number (1523088).

Almost surely, 2^21065898 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21065898, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24369408).

21065898 is an abundant number, since it is smaller than the sum of its proper divisors (27672918).

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

21065898 is a wasteful number, since it uses less digits than its factorization.

21065898 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6138.

The product of its (nonzero) digits is 34560, while the sum is 39.

The square root of 21065898 is about 4589.7601244509. The cubic root of 21065898 is about 276.1806997738.

The spelling of 21065898 in words is "twenty-one million, sixty-five thousand, eight hundred ninety-eight".