212151311521 has 4 divisors (see below), whose sum is σ = 224630800452. Its totient is φ = 199671822592.

The previous prime is 212151311479. The next prime is 212151311597. The reversal of 212151311521 is 125113151212.

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

It can be written as a sum of positive squares in 2 ways, for example, as 151679091600 + 60472219921 = 389460^2 + 245911^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-212151311521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (212151311821) 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, 6239744440 + ... + 6239744473.

It is an arithmetic number, because the mean of its divisors is an integer number (56157700113).

Almost surely, 2^212151311521 is an apocalyptic number.

It is an amenable number.

212151311521 is a deficient number, since it is larger than the sum of its proper divisors (12479488931).

212151311521 is a wasteful number, since it uses less digits than its factorization.

212151311521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12479488930.

The product of its digits is 600, while the sum is 25.

Adding to 212151311521 its reverse (125113151212), we get a palindrome (337264462733).

The spelling of 212151311521 in words is "two hundred twelve billion, one hundred fifty-one million, three hundred eleven thousand, five hundred twenty-one".