20999700 has 54 divisors (see below), whose sum is σ = 65825214. Its totient is φ = 5599680.

The previous prime is 20999681. The next prime is 20999711. The reversal of 20999700 is 799902.

It can be written as a sum of positive squares in 3 ways, for example, as 41616 + 20958084 = 204^2 + 4578^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 10767 + ... + 12566.

Almost surely, 2^20999700 is an apocalyptic number.

20999700 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20999700 is an abundant number, since it is smaller than the sum of its proper divisors (44825514).

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

20999700 is a wasteful number, since it uses less digits than its factorization.

20999700 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23353 (or 23343 counting only the distinct ones).

The product of its (nonzero) digits is 10206, while the sum is 36.

The square root of 20999700 is about 4582.5429621554. The cubic root of 20999700 is about 275.8911038584.

The spelling of 20999700 in words is "twenty million, nine hundred ninety-nine thousand, seven hundred".