213778917 has 12 divisors (see below), whose sum is σ = 336863904. Its totient is φ = 129562920.

The previous prime is 213778913. The next prime is 213778921. The reversal of 213778917 is 719877312.

213778917 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (213778913) and next prime (213778921).

It is not a de Polignac number, because 213778917 - 2² = 213778913 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213778913) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1079593 + ... + 1079790.

It is an arithmetic number, because the mean of its divisors is an integer number (28071992).

Almost surely, 2^213778917 is an apocalyptic number.

It is an amenable number.

213778917 is a deficient number, since it is larger than the sum of its proper divisors (123084987).

213778917 is a wasteful number, since it uses less digits than its factorization.

213778917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2159400 (or 2159397 counting only the distinct ones).

The product of its digits is 148176, while the sum is 45.

The square root of 213778917 is about 14621.1804243023. The cubic root of 213778917 is about 597.9363520660.

The spelling of 213778917 in words is "two hundred thirteen million, seven hundred seventy-eight thousand, nine hundred seventeen".