21155234 has 4 divisors (see below), whose sum is σ = 31732854. Its totient is φ = 10577616.

The previous prime is 21155219. The next prime is 21155257. The reversal of 21155234 is 43255112.

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., 21114025 + 41209 = 4595^2 + 203^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5288807 + ... + 5288810.

Almost surely, 2^21155234 is an apocalyptic number.

21155234 is a deficient number, since it is larger than the sum of its proper divisors (10577620).

21155234 is a wasteful number, since it uses less digits than its factorization.

21155234 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10577619.

The product of its digits is 1200, while the sum is 23.

The square root of 21155234 is about 4599.4819273479. The cubic root of 21155234 is about 276.5705570913.

The spelling of 21155234 in words is "twenty-one million, one hundred fifty-five thousand, two hundred thirty-four".