213121870837 has 2 divisors, whose sum is σ = 213121870838. Its totient is φ = 213121870836.

The previous prime is 213121870823. The next prime is 213121870847. The reversal of 213121870837 is 738078121312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 199581988516 + 13539882321 = 446746^2 + 116361^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-213121870837 is a prime.

It is a super-2 number, since 2×213121870837² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 213121870793 and 213121870802.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213121870847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106560935418 + 106560935419.

It is an arithmetic number, because the mean of its divisors is an integer number (106560935419).

Almost surely, 2^213121870837 is an apocalyptic number.

It is an amenable number.

213121870837 is a deficient number, since it is larger than the sum of its proper divisors (1).

213121870837 is an equidigital number, since it uses as much as digits as its factorization.

213121870837 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 112896, while the sum is 43.

The spelling of 213121870837 in words is "two hundred thirteen billion, one hundred twenty-one million, eight hundred seventy thousand, eight hundred thirty-seven".