20913231 has 8 divisors (see below), whose sum is σ = 27941760. Its totient is φ = 13913432.

The previous prime is 20913229. The next prime is 20913271. The reversal of 20913231 is 13231902.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 20913231 - 2¹ = 20913229 is a prime.

It is a super-2 number, since 2×20913231² = 874726461718722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20913198 and 20913207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20913271) 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, 5421 + ... + 8438.

It is an arithmetic number, because the mean of its divisors is an integer number (3492720).

Almost surely, 2^20913231 is an apocalyptic number.

20913231 is a deficient number, since it is larger than the sum of its proper divisors (7028529).

20913231 is a wasteful number, since it uses less digits than its factorization.

20913231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14365.

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

The square root of 20913231 is about 4573.0986212851. The cubic root of 20913231 is about 275.5119104033.

The spelling of 20913231 in words is "twenty million, nine hundred thirteen thousand, two hundred thirty-one".