215747993 has 4 divisors (see below), whose sum is σ = 215808528. Its totient is φ = 215687460.

The previous prime is 215747989. The next prime is 215748007. The reversal of 215747993 is 399747512.

215747993 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 215747993 - 2² = 215747989 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (215747093) 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, 24563 + ... + 32168.

It is an arithmetic number, because the mean of its divisors is an integer number (53952132).

Almost surely, 2^215747993 is an apocalyptic number.

It is an amenable number.

215747993 is a deficient number, since it is larger than the sum of its proper divisors (60535).

215747993 is an equidigital number, since it uses as much as digits as its factorization.

215747993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60534.

The product of its digits is 476280, while the sum is 47.

The square root of 215747993 is about 14688.3625023350. The cubic root of 215747993 is about 599.7665693805.

The spelling of 215747993 in words is "two hundred fifteen million, seven hundred forty-seven thousand, nine hundred ninety-three".