21213600155 has 16 divisors (see below), whose sum is σ = 28241222400. Its totient is φ = 15166577760.

The previous prime is 21213600151. The next prime is 21213600169. The reversal of 21213600155 is 55100631212.

It is not a de Polignac number, because 21213600155 - 2² = 21213600151 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21213600151) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3265415 + ... + 3271904.

It is an arithmetic number, because the mean of its divisors is an integer number (1765076400).

Almost surely, 2^21213600155 is an apocalyptic number.

21213600155 is a deficient number, since it is larger than the sum of its proper divisors (7027622245).

21213600155 is a wasteful number, since it uses less digits than its factorization.

21213600155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6537394.

The product of its (nonzero) digits is 1800, while the sum is 26.

The spelling of 21213600155 in words is "twenty-one billion, two hundred thirteen million, six hundred thousand, one hundred fifty-five".