21097726 has 16 divisors (see below), whose sum is σ = 34335504. Its totient is φ = 9664704.

The previous prime is 21097723. The next prime is 21097753. The reversal of 21097726 is 62779012.

It is a super-2 number, since 2×21097726² = 890228084742152, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21097691 and 21097700.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21097723) 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, 601 + ... + 6523.

It is an arithmetic number, because the mean of its divisors is an integer number (2145969).

Almost surely, 2^21097726 is an apocalyptic number.

21097726 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21097726 is a deficient number, since it is larger than the sum of its proper divisors (13237778).

21097726 is a wasteful number, since it uses less digits than its factorization.

21097726 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6075.

The product of its (nonzero) digits is 10584, while the sum is 34.

The square root of 21097726 is about 4593.2260993772. The cubic root of 21097726 is about 276.3197215554.

The spelling of 21097726 in words is "twenty-one million, ninety-seven thousand, seven hundred twenty-six".