215523131 has 2 divisors, whose sum is σ = 215523132. Its totient is φ = 215523130.

The previous prime is 215523103. The next prime is 215523149. The reversal of 215523131 is 131325512.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-215523131 is a prime.

It is a super-2 number, since 2×215523131² = 92900439992086322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 215523097 and 215523106.

It is not a weakly prime, because it can be changed into another prime (215543131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107761565 + 107761566.

It is an arithmetic number, because the mean of its divisors is an integer number (107761566).

Almost surely, 2^215523131 is an apocalyptic number.

215523131 is a deficient number, since it is larger than the sum of its proper divisors (1).

215523131 is an equidigital number, since it uses as much as digits as its factorization.

215523131 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 900, while the sum is 23.

The square root of 215523131 is about 14680.7060797497. The cubic root of 215523131 is about 599.5581292933.

Adding to 215523131 its reverse (131325512), we get a palindrome (346848643).

The spelling of 215523131 in words is "two hundred fifteen million, five hundred twenty-three thousand, one hundred thirty-one".