215801421 has 8 divisors (see below), whose sum is σ = 313893024. Its totient is φ = 130788720.

The previous prime is 215801401. The next prime is 215801431. The reversal of 215801421 is 124108512.

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

It is not a de Polignac number, because 215801421 - 2⁵ = 215801389 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 215801391 and 215801400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215801401) 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 in 7 ways as a sum of consecutive naturals, for example, 3269686 + ... + 3269751.

It is an arithmetic number, because the mean of its divisors is an integer number (39236628).

Almost surely, 2^215801421 is an apocalyptic number.

It is an amenable number.

215801421 is a deficient number, since it is larger than the sum of its proper divisors (98091603).

215801421 is a wasteful number, since it uses less digits than its factorization.

215801421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6539451.

The product of its (nonzero) digits is 640, while the sum is 24.

The square root of 215801421 is about 14690.1811084820. The cubic root of 215801421 is about 599.8160741801.

Adding to 215801421 its reverse (124108512), we get a palindrome (339909933).

The spelling of 215801421 in words is "two hundred fifteen million, eight hundred one thousand, four hundred twenty-one".