215013721 has 8 divisors (see below), whose sum is σ = 232525440. Its totient is φ = 197640912.

The previous prime is 215013707. The next prime is 215013731. The reversal of 215013721 is 127310512.

It is a happy number.

215013721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 215013721 - 2¹¹ = 215011673 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 215013692 and 215013701.

It is not an unprimeable number, because it can be changed into a prime (215013731) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31495 + ... + 37708.

It is an arithmetic number, because the mean of its divisors is an integer number (29065680).

Almost surely, 2^215013721 is an apocalyptic number.

It is an amenable number.

215013721 is a deficient number, since it is larger than the sum of its proper divisors (17511719).

215013721 is a wasteful number, since it uses less digits than its factorization.

215013721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69455.

The product of its (nonzero) digits is 420, while the sum is 22.

The square root of 215013721 is about 14663.3461733671. The cubic root of 215013721 is about 599.0853852118.

The spelling of 215013721 in words is "two hundred fifteen million, thirteen thousand, seven hundred twenty-one".