21213612402123 has 4 divisors (see below), whose sum is σ = 28284816536168. Its totient is φ = 14142408268080.

The previous prime is 21213612402109. The next prime is 21213612402149. The reversal of 21213612402123 is 32120421631212.

It is a happy number.

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

It is not a de Polignac number, because 21213612402123 - 2⁴ = 21213612402107 is a prime.

It is a super-2 number, since 2×21213612402123² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21213612402223) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3535602067018 + ... + 3535602067023.

It is an arithmetic number, because the mean of its divisors is an integer number (7071204134042).

Almost surely, 2^{21213612402123} is an apocalyptic number.

21213612402123 is a deficient number, since it is larger than the sum of its proper divisors (7071204134045).

21213612402123 is an equidigital number, since it uses as much as digits as its factorization.

21213612402123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7071204134044.

The product of its (nonzero) digits is 6912, while the sum is 30.

The spelling of 21213612402123 in words is "twenty-one trillion, two hundred thirteen billion, six hundred twelve million, four hundred two thousand, one hundred twenty-three".