21200155 has 8 divisors (see below), whose sum is σ = 25570512. Its totient is φ = 16873248.

The previous prime is 21200147. The next prime is 21200171. The reversal of 21200155 is 55100212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21200155 - 2³ = 21200147 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9777 + ... + 11746.

It is an arithmetic number, because the mean of its divisors is an integer number (3196314).

Almost surely, 2^21200155 is an apocalyptic number.

21200155 is a deficient number, since it is larger than the sum of its proper divisors (4370357).

21200155 is a wasteful number, since it uses less digits than its factorization.

21200155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21725.

The product of its (nonzero) digits is 100, while the sum is 16.

The square root of 21200155 is about 4604.3626051822. The cubic root of 21200155 is about 276.7661752344.

Adding to 21200155 its reverse (55100212), we get a palindrome (76300367).

The spelling of 21200155 in words is "twenty-one million, two hundred thousand, one hundred fifty-five".