215640426 has 8 divisors (see below), whose sum is σ = 431280864. Its totient is φ = 71880140.

The previous prime is 215640421. The next prime is 215640437. The reversal of 215640426 is 624046512.

It is a sphenic number, since it is the product of 3 distinct primes.

215640426 is an admirable number.

It is a super-2 number, since 2×215640426² = 93001586650922952, which contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 215640393 and 215640402.

It is not an unprimeable number, because it can be changed into a prime (215640421) 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, 17970030 + ... + 17970041.

It is an arithmetic number, because the mean of its divisors is an integer number (53910108).

Almost surely, 2^215640426 is an apocalyptic number.

215640426 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

215640426 is a wasteful number, since it uses less digits than its factorization.

215640426 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35940076.

The product of its (nonzero) digits is 11520, while the sum is 30.

The square root of 215640426 is about 14684.7004055241. The cubic root of 215640426 is about 599.6668761929. Note that the first 3 decimals are identical.

Adding to 215640426 its reverse (624046512), we get a palindrome (839686938).

The spelling of 215640426 in words is "two hundred fifteen million, six hundred forty thousand, four hundred twenty-six".