213940778 has 4 divisors (see below), whose sum is σ = 320911170. Its totient is φ = 106970388.

The previous prime is 213940777. The next prime is 213940787. The reversal of 213940778 is 877049312.

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

It can be written as a sum of positive squares in only one way, i.e., 213656689 + 284089 = 14617^2 + 533^2 .

It is not an unprimeable number, because it can be changed into a prime (213940777) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 53485193 + ... + 53485196.

Almost surely, 2^213940778 is an apocalyptic number.

213940778 is a deficient number, since it is larger than the sum of its proper divisors (106970392).

213940778 is a wasteful number, since it uses less digits than its factorization.

213940778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106970391.

The product of its (nonzero) digits is 84672, while the sum is 41.

The square root of 213940778 is about 14626.7145319788. The cubic root of 213940778 is about 598.0872215740.

The spelling of 213940778 in words is "two hundred thirteen million, nine hundred forty thousand, seven hundred seventy-eight".