20999031 has 16 divisors (see below), whose sum is σ = 28574208. Its totient is φ = 13714400.

The previous prime is 20999021. The next prime is 20999039. The reversal of 20999031 is 13099902.

It is a cyclic number.

It is not a de Polignac number, because 20999031 - 2¹⁰ = 20998007 is a prime.

It is a super-2 number, since 2×20999031² = 881918605877922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20998983 and 20999001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20999039) 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 15 ways as a sum of consecutive naturals, for example, 66085 + ... + 66401.

It is an arithmetic number, because the mean of its divisors is an integer number (1785888).

Almost surely, 2^20999031 is an apocalyptic number.

20999031 is a deficient number, since it is larger than the sum of its proper divisors (7575177).

20999031 is a wasteful number, since it uses less digits than its factorization.

20999031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 702.

The product of its (nonzero) digits is 4374, while the sum is 33.

The square root of 20999031 is about 4582.4699671684. The cubic root of 20999031 is about 275.8881740847. Note that the first 3 decimals are identical.

The spelling of 20999031 in words is "twenty million, nine hundred ninety-nine thousand, thirty-one".