213782921 has 6 divisors (see below), whose sum is σ = 234984666. Its totient is φ = 194348000.

The previous prime is 213782869. The next prime is 213782951. The reversal of 213782921 is 129287312.

It can be written as a sum of positive squares in only one way, i.e., 162817600 + 50965321 = 12760^2 + 7139^2 .

It is not a de Polignac number, because 213782921 - 2¹⁴ = 213766537 is a prime.

It is a super-2 number, since 2×213782921² = 91406274622584482, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (213782951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 883280 + ... + 883521.

It is an arithmetic number, because the mean of its divisors is an integer number (39164111).

Almost surely, 2^213782921 is an apocalyptic number.

It is an amenable number.

213782921 is a deficient number, since it is larger than the sum of its proper divisors (21201745).

213782921 is a wasteful number, since it uses less digits than its factorization.

213782921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1766823 (or 1766812 counting only the distinct ones).

The product of its digits is 12096, while the sum is 35.

The square root of 213782921 is about 14621.3173483103. The cubic root of 213782921 is about 597.9400850849.

It can be divided in two parts, 2137 and 82921, that added together give a palindrome (85058).

The spelling of 213782921 in words is "two hundred thirteen million, seven hundred eighty-two thousand, nine hundred twenty-one".