2151212251 has 4 divisors (see below), whose sum is σ = 2152542600. Its totient is φ = 2149881904.

The previous prime is 2151212221. The next prime is 2151212263. The reversal of 2151212251 is 1522121512.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 2151212251 - 2¹¹ = 2151210203 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2151212201) 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, 662746 + ... + 665983.

It is an arithmetic number, because the mean of its divisors is an integer number (538135650).

Almost surely, 2^2151212251 is an apocalyptic number.

2151212251 is a deficient number, since it is larger than the sum of its proper divisors (1330349).

2151212251 is a wasteful number, since it uses less digits than its factorization.

2151212251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1330348.

The product of its digits is 400, while the sum is 22.

The square root of 2151212251 is about 46381.1626740857. The cubic root of 2151212251 is about 1290.9054098831.

Adding to 2151212251 its reverse (1522121512), we get a palindrome (3673333763).

The spelling of 2151212251 in words is "two billion, one hundred fifty-one million, two hundred twelve thousand, two hundred fifty-one".