21210214155 has 32 divisors (see below), whose sum is σ = 37807076160. Its totient is φ = 10081881600.

The previous prime is 21210214139. The next prime is 21210214199. The reversal of 21210214155 is 55141201212.

It is a happy number.

It is not a de Polignac number, because 21210214155 - 2⁴ = 21210214139 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1869696 + ... + 1881005.

It is an arithmetic number, because the mean of its divisors is an integer number (1181471130).

Almost surely, 2^21210214155 is an apocalyptic number.

21210214155 is a deficient number, since it is larger than the sum of its proper divisors (16596862005).

21210214155 is a wasteful number, since it uses less digits than its factorization.

21210214155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3750751.

The product of its (nonzero) digits is 800, while the sum is 24.

Adding to 21210214155 its reverse (55141201212), we get a palindrome (76351415367).

The spelling of 21210214155 in words is "twenty-one billion, two hundred ten million, two hundred fourteen thousand, one hundred fifty-five".