215212177909 has 4 divisors (see below), whose sum is σ = 227871717804. Its totient is φ = 202552638016.

The previous prime is 215212177897. The next prime is 215212177919. The reversal of 215212177909 is 909771212512.

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 74359836100 + 140852341809 = 272690^2 + 375303^2 .

It is a cyclic number.

It is not a de Polignac number, because 215212177909 - 2⁵ = 215212177877 is a prime.

It is a super-2 number, since 2×215212177909² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215212177919) 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, 6329769922 + ... + 6329769955.

It is an arithmetic number, because the mean of its divisors is an integer number (56967929451).

Almost surely, 2^215212177909 is an apocalyptic number.

It is an amenable number.

215212177909 is a deficient number, since it is larger than the sum of its proper divisors (12659539895).

215212177909 is a wasteful number, since it uses less digits than its factorization.

215212177909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12659539894.

The product of its (nonzero) digits is 158760, while the sum is 46.

The spelling of 215212177909 in words is "two hundred fifteen billion, two hundred twelve million, one hundred seventy-seven thousand, nine hundred nine".