21066031 has 8 divisors (see below), whose sum is σ = 24567200. Its totient is φ = 18056304.

The previous prime is 21066013. The next prime is 21066049. The reversal of 21066031 is 13066012.

21066031 is nontrivially palindromic in base 15.

It is an interprime number because it is at equal distance from previous prime (21066013) and next prime (21066049).

It is not a de Polignac number, because 21066031 - 2¹¹ = 21063983 is a prime.

It is a super-2 number, since 2×21066031² = 887555324185922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21066931) 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, 30366 + ... + 31051.

It is an arithmetic number, because the mean of its divisors is an integer number (3070900).

Almost surely, 2^21066031 is an apocalyptic number.

21066031 is a deficient number, since it is larger than the sum of its proper divisors (3501169).

21066031 is an frugal number, since it uses more digits than its factorization.

21066031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61438 (or 61424 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 19.

The square root of 21066031 is about 4589.7746132027. The cubic root of 21066031 is about 276.1812809968.

Subtracting from 21066031 its sum of digits (19), we obtain a palindrome (21066012).

The spelling of 21066031 in words is "twenty-one million, sixty-six thousand, thirty-one".