20899280 has 20 divisors (see below), whose sum is σ = 48591012. Its totient is φ = 8359680.

The previous prime is 20899261. The next prime is 20899283. The reversal of 20899280 is 8299802.

It can be written as a sum of positive squares in 2 ways, for example, as 13630864 + 7268416 = 3692^2 + 2696^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20899283) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 130541 + ... + 130700.

Almost surely, 2^20899280 is an apocalyptic number.

20899280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20899280 is an abundant number, since it is smaller than the sum of its proper divisors (27691732).

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

20899280 is a wasteful number, since it uses less digits than its factorization.

20899280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 261254 (or 261248 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 38.

The square root of 20899280 is about 4571.5730334317. The cubic root of 20899280 is about 275.4506330605.

The spelling of 20899280 in words is "twenty million, eight hundred ninety-nine thousand, two hundred eighty".