21097456 has 20 divisors (see below), whose sum is σ = 41571000. Its totient is φ = 10369472.

The previous prime is 21097441. The next prime is 21097457. The reversal of 21097456 is 65479012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21097457) 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 3 ways as a sum of consecutive naturals, for example, 10231 + ... + 12118.

It is an arithmetic number, because the mean of its divisors is an integer number (2078550).

Almost surely, 2^21097456 is an apocalyptic number.

It is an amenable number.

21097456 is a deficient number, since it is larger than the sum of its proper divisors (20473544).

21097456 is a wasteful number, since it uses less digits than its factorization.

21097456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22416 (or 22410 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 34.

The square root of 21097456 is about 4593.1967081761. The cubic root of 21097456 is about 276.3185428084.

It can be divided in two parts, 2 and 1097456, that multiplied together give a palindrome (2194912).

The spelling of 21097456 in words is "twenty-one million, ninety-seven thousand, four hundred fifty-six".