21136898 has 4 divisors (see below), whose sum is σ = 31705350. Its totient is φ = 10568448.

The previous prime is 21136891. The next prime is 21136903. The reversal of 21136898 is 89863112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 21132409 + 4489 = 4597^2 + 67^2 .

It is not an unprimeable number, because it can be changed into a prime (21136891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5284223 + ... + 5284226.

Almost surely, 2^21136898 is an apocalyptic number.

21136898 is a deficient number, since it is larger than the sum of its proper divisors (10568452).

21136898 is a wasteful number, since it uses less digits than its factorization.

21136898 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10568451.

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

The square root of 21136898 is about 4597.4882272824. The cubic root of 21136898 is about 276.4906294546.

The spelling of 21136898 in words is "twenty-one million, one hundred thirty-six thousand, eight hundred ninety-eight".