21431036 has 18 divisors (see below), whose sum is σ = 41224680. Its totient is φ = 9741160.

The previous prime is 21431023. The next prime is 21431057. The reversal of 21431036 is 63013412.

It is a junction number, because it is equal to n+sod(n) for n = 21430999 and 21431017.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 21656 + ... + 22623.

It is an arithmetic number, because the mean of its divisors is an integer number (2290260).

Almost surely, 2^21431036 is an apocalyptic number.

It is an amenable number.

21431036 is a deficient number, since it is larger than the sum of its proper divisors (19793644).

21431036 is a wasteful number, since it uses less digits than its factorization.

21431036 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44305 (or 44292 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 20.

The square root of 21431036 is about 4629.3666953483. The cubic root of 21431036 is about 277.7672603070.

Adding to 21431036 its reverse (63013412), we get a palindrome (84444448).

The spelling of 21431036 in words is "twenty-one million, four hundred thirty-one thousand, thirty-six".