21033431 has 8 divisors (see below), whose sum is σ = 21993984. Its totient is φ = 20076760.

The previous prime is 21033413. The next prime is 21033433. The reversal of 21033431 is 13433012.

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 21033431 - 2⁶ = 21033367 is a prime.

It is a super-2 number, since 2×21033431² = 884810439263522, 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 (21033433) 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 7 ways as a sum of consecutive naturals, for example, 19886 + ... + 20916.

It is an arithmetic number, because the mean of its divisors is an integer number (2749248).

Almost surely, 2^21033431 is an apocalyptic number.

21033431 is a deficient number, since it is larger than the sum of its proper divisors (960553).

21033431 is a wasteful number, since it uses less digits than its factorization.

21033431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1941.

The product of its (nonzero) digits is 216, while the sum is 17.

The square root of 21033431 is about 4586.2218655447. The cubic root of 21033431 is about 276.0387425485.

Adding to 21033431 its reverse (13433012), we get a palindrome (34466443).

The spelling of 21033431 in words is "twenty-one million, thirty-three thousand, four hundred thirty-one".