20213391 has 32 divisors (see below), whose sum is σ = 31477248. Its totient is φ = 11402240.

The previous prime is 20213353. The next prime is 20213399. The reversal of 20213391 is 19331202.

It is a happy number.

It is not a de Polignac number, because 20213391 - 2¹⁴ = 20197007 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20213399) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 76726 + ... + 76988.

It is an arithmetic number, because the mean of its divisors is an integer number (983664).

Almost surely, 2^20213391 is an apocalyptic number.

20213391 is a deficient number, since it is larger than the sum of its proper divisors (11263857).

20213391 is a wasteful number, since it uses less digits than its factorization.

20213391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 431.

The product of its (nonzero) digits is 324, while the sum is 21.

The square root of 20213391 is about 4495.9304932350. The cubic root of 20213391 is about 272.4037356014.

Adding to 20213391 its reverse (19331202), we get a palindrome (39544593).

The spelling of 20213391 in words is "twenty million, two hundred thirteen thousand, three hundred ninety-one".