212138281861 has 16 divisors (see below), whose sum is σ = 233508866688. Its totient is φ = 192710253120.

The previous prime is 212138281787. The next prime is 212138281879. The reversal of 212138281861 is 168182831212.

It is not a de Polignac number, because 212138281861 - 2¹⁵ = 212138249093 is a prime.

It is a super-5 number, since 5×212138281861⁵ (a number of 58 digits) contains 55555 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212138281891) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1761181 + ... + 1877773.

It is an arithmetic number, because the mean of its divisors is an integer number (14594304168).

Almost surely, 2^212138281861 is an apocalyptic number.

It is an amenable number.

212138281861 is a deficient number, since it is larger than the sum of its proper divisors (21370584827).

212138281861 is a wasteful number, since it uses less digits than its factorization.

212138281861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117993 (or 117971 counting only the distinct ones).

The product of its digits is 73728, while the sum is 43.

The spelling of 212138281861 in words is "two hundred twelve billion, one hundred thirty-eight million, two hundred eighty-one thousand, eight hundred sixty-one".