21250998 has 40 divisors (see below), whose sum is σ = 47907288. Its totient is φ = 7040736.

The previous prime is 21250979. The next prime is 21251017. The reversal of 21250998 is 89905212.

It is an interprime number because it is at equal distance from previous prime (21250979) and next prime (21251017).

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 37465 + ... + 38027.

Almost surely, 2^21250998 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21250998, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23953644).

21250998 is an abundant number, since it is smaller than the sum of its proper divisors (26656290).

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

21250998 is a wasteful number, since it uses less digits than its factorization.

21250998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 810 (or 801 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 21250998 is about 4609.8804756740. The cubic root of 21250998 is about 276.9872489102.

The spelling of 21250998 in words is "twenty-one million, two hundred fifty thousand, nine hundred ninety-eight".