215400253 has 4 divisors (see below), whose sum is σ = 215749980. Its totient is φ = 215050528.

The previous prime is 215400223. The next prime is 215400271. The reversal of 215400253 is 352004512.

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 21132409 + 194267844 = 4597^2 + 13938^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-215400253 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215400223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 173938 + ... + 175171.

It is an arithmetic number, because the mean of its divisors is an integer number (53937495).

Almost surely, 2^215400253 is an apocalyptic number.

It is an amenable number.

215400253 is a deficient number, since it is larger than the sum of its proper divisors (349727).

215400253 is an equidigital number, since it uses as much as digits as its factorization.

215400253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 349726.

The product of its (nonzero) digits is 1200, while the sum is 22.

The square root of 215400253 is about 14676.5204663776. The cubic root of 215400253 is about 599.4441639398. Note that the first 3 decimals are identical.

Adding to 215400253 its reverse (352004512), we get a palindrome (567404765).

The spelling of 215400253 in words is "two hundred fifteen million, four hundred thousand, two hundred fifty-three".