21200138 has 4 divisors (see below), whose sum is σ = 31800210. Its totient is φ = 10600068.

The previous prime is 21200129. The next prime is 21200147. The reversal of 21200138 is 83100212.

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

It is an interprime number because it is at equal distance from previous prime (21200129) and next prime (21200147).

It can be written as a sum of positive squares in only one way, i.e., 21003889 + 196249 = 4583^2 + 443^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5300033 + ... + 5300036.

Almost surely, 2^21200138 is an apocalyptic number.

21200138 is a deficient number, since it is larger than the sum of its proper divisors (10600072).

21200138 is a wasteful number, since it uses less digits than its factorization.

21200138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10600071.

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 21200138 is about 4604.3607591065. The cubic root of 21200138 is about 276.7661012565.

The spelling of 21200138 in words is "twenty-one million, two hundred thousand, one hundred thirty-eight".