2123213821 has 2 divisors, whose sum is σ = 2123213822. Its totient is φ = 2123213820.

The previous prime is 2123213783. The next prime is 2123213837. The reversal of 2123213821 is 1283123212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1625299225 + 497914596 = 40315^2 + 22314^2 .

It is a cyclic number.

It is not a de Polignac number, because 2123213821 - 2¹³ = 2123205629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2123217821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1061606910 + 1061606911.

It is an arithmetic number, because the mean of its divisors is an integer number (1061606911).

Almost surely, 2^2123213821 is an apocalyptic number.

It is an amenable number.

2123213821 is a deficient number, since it is larger than the sum of its proper divisors (1).

2123213821 is an equidigital number, since it uses as much as digits as its factorization.

2123213821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 25.

The square root of 2123213821 is about 46078.3443821498. The cubic root of 2123213821 is about 1285.2804771639.

It can be divided in two parts, 21232 and 13821, that added together give a palindrome (35053).

The spelling of 2123213821 in words is "two billion, one hundred twenty-three million, two hundred thirteen thousand, eight hundred twenty-one".