21097850 has 24 divisors (see below), whose sum is σ = 41552028. Its totient is φ = 7942400.

The previous prime is 21097841. The next prime is 21097859. The reversal of 21097850 is 5879012.

It is an interprime number because it is at equal distance from previous prime (21097841) and next prime (21097859).

It can be written as a sum of positive squares in 6 ways, for example, as 6405961 + 14691889 = 2531^2 + 3833^2 .

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (21097859) 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, 11561 + ... + 13260.

Almost surely, 2^21097850 is an apocalyptic number.

21097850 is a deficient number, since it is larger than the sum of its proper divisors (20454178).

21097850 is a wasteful number, since it uses less digits than its factorization.

21097850 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24850 (or 24845 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 32.

The square root of 21097850 is about 4593.2395974954. The cubic root of 21097850 is about 276.3202629025.

The spelling of 21097850 in words is "twenty-one million, ninety-seven thousand, eight hundred fifty".