215242251 has 48 divisors (see below), whose sum is σ = 347493888. Its totient is φ = 118070400.

The previous prime is 215242249. The next prime is 215242259. The reversal of 215242251 is 152242512.

It is not a de Polignac number, because 215242251 - 2¹ = 215242249 is a prime.

It is not an unprimeable number, because it can be changed into a prime (215242259) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 427666 + ... + 428168.

It is an arithmetic number, because the mean of its divisors is an integer number (7239456).

Almost surely, 2^215242251 is an apocalyptic number.

215242251 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

215242251 is a deficient number, since it is larger than the sum of its proper divisors (132251637).

215242251 is a wasteful number, since it uses less digits than its factorization.

215242251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 632 (or 625 counting only the distinct ones).

The product of its digits is 1600, while the sum is 24.

The square root of 215242251 is about 14671.1366635309. The cubic root of 215242251 is about 599.2975585031.

Adding to 215242251 its reverse (152242512), we get a palindrome (367484763).

The spelling of 215242251 in words is "two hundred fifteen million, two hundred forty-two thousand, two hundred fifty-one".