21898628082409 has 27 divisors (see below), whose sum is σ = 23857792604919. Its totient is φ = 20091194575920.

The previous prime is 21898628082361. The next prime is 21898628082467. The reversal of 21898628082409 is 90428082689812.

The square root of 21898628082409 is 4679597.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 3239442024025 + 18659186058384 = 1799845^2 + 4319628^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21898628082409 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21898628082809) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 10889421214 + ... + 10889423224.

Almost surely, 2^{21898628082409} is an apocalyptic number.

21898628082409 is the 4679597-th square number.

21898628082409 is the 2339799-th centered octagonal number.

It is an amenable number.

21898628082409 is a deficient number, since it is larger than the sum of its proper divisors (1959164522510).

21898628082409 is an frugal number, since it uses more digits than its factorization.

21898628082409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4406 (or 2203 counting only the distinct ones).

The product of its (nonzero) digits is 63700992, while the sum is 67.

The spelling of 21898628082409 in words is "twenty-one trillion, eight hundred ninety-eight billion, six hundred twenty-eight million, eighty-two thousand, four hundred nine".