21099003858 has 24 divisors (see below), whose sum is σ = 48403597788. Its totient is φ = 6619295232.

The previous prime is 21099003857. The next prime is 21099003859. The reversal of 21099003858 is 85830099012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21099003857) and next prime (21099003859).

It can be written as a sum of positive squares in 2 ways, for example, as 20988186129 + 110817729 = 144873^2 + 10527^2 .

It is not an unprimeable number, because it can be changed into a prime (21099003857) 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, 34475191 + ... + 34475802.

Almost surely, 2^21099003858 is an apocalyptic number.

21099003858 is an abundant number, since it is smaller than the sum of its proper divisors (27304593930).

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

21099003858 is a wasteful number, since it uses less digits than its factorization.

21099003858 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68951018 (or 68951015 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 45.

The spelling of 21099003858 in words is "twenty-one billion, ninety-nine million, three thousand, eight hundred fifty-eight".