213386781 has 8 divisors (see below), whose sum is σ = 284593120. Its totient is φ = 142219152.

The previous prime is 213386779. The next prime is 213386791. The reversal of 213386781 is 187683312.

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

It is not a de Polignac number, because 213386781 - 2¹ = 213386779 is a prime.

It is a super-2 number, since 2×213386781² = 91067836611083922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213386731) 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, 7590 + ... + 22008.

It is an arithmetic number, because the mean of its divisors is an integer number (35574140).

Almost surely, 2^213386781 is an apocalyptic number.

It is an amenable number.

213386781 is a deficient number, since it is larger than the sum of its proper divisors (71206339).

213386781 is a wasteful number, since it uses less digits than its factorization.

213386781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19355.

The product of its digits is 48384, while the sum is 39.

The square root of 213386781 is about 14607.7644080126. The cubic root of 213386781 is about 597.5705288383.

The spelling of 213386781 in words is "two hundred thirteen million, three hundred eighty-six thousand, seven hundred eighty-one".