21212021879 has 2 divisors, whose sum is σ = 21212021880. Its totient is φ = 21212021878.

The previous prime is 21212021869. The next prime is 21212021891. The reversal of 21212021879 is 97812021212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21212021879 - 2¹⁶ = 21211956343 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21212021849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606010939 + 10606010940.

It is an arithmetic number, because the mean of its divisors is an integer number (10606010940).

Almost surely, 2^21212021879 is an apocalyptic number.

21212021879 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212021879 is an equidigital number, since it uses as much as digits as its factorization.

21212021879 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8064, while the sum is 35.

The spelling of 21212021879 in words is "twenty-one billion, two hundred twelve million, twenty-one thousand, eight hundred seventy-nine".