213977945 has 4 divisors (see below), whose sum is σ = 256773540. Its totient is φ = 171182352.

The previous prime is 213977941. The next prime is 213977957. The reversal of 213977945 is 549779312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 70744921 + 143233024 = 8411^2 + 11968^2 .

It is a cyclic number.

It is not a de Polignac number, because 213977945 - 2² = 213977941 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 213977945.

It is not an unprimeable number, because it can be changed into a prime (213977941) 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, 21397790 + ... + 21397799.

It is an arithmetic number, because the mean of its divisors is an integer number (64193385).

Almost surely, 2^213977945 is an apocalyptic number.

It is an amenable number.

213977945 is a deficient number, since it is larger than the sum of its proper divisors (42795595).

213977945 is an equidigital number, since it uses as much as digits as its factorization.

213977945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42795594.

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

The square root of 213977945 is about 14627.9849945233. The cubic root of 213977945 is about 598.1218539317.

The spelling of 213977945 in words is "two hundred thirteen million, nine hundred seventy-seven thousand, nine hundred forty-five".