215221172 has 6 divisors (see below), whose sum is σ = 376637058. Its totient is φ = 107610584.

The previous prime is 215221159. The next prime is 215221183. The reversal of 215221172 is 271122512.

It can be written as a sum of positive squares in only one way, i.e., 211237156 + 3984016 = 14534^2 + 1996^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 26902643 + ... + 26902650.

It is an arithmetic number, because the mean of its divisors is an integer number (62772843).

Almost surely, 2^215221172 is an apocalyptic number.

It is an amenable number.

215221172 is a deficient number, since it is larger than the sum of its proper divisors (161415886).

215221172 is a wasteful number, since it uses less digits than its factorization.

215221172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53805297 (or 53805295 counting only the distinct ones).

The product of its digits is 560, while the sum is 23.

The square root of 215221172 is about 14670.4182626127. The cubic root of 215221172 is about 599.2779944915.

Adding to 215221172 its reverse (271122512), we get a palindrome (486343684).

The spelling of 215221172 in words is "two hundred fifteen million, two hundred twenty-one thousand, one hundred seventy-two".