21097746 has 24 divisors (see below), whose sum is σ = 47405904. Its totient is φ = 7032420.

The previous prime is 21097723. The next prime is 21097753. The reversal of 21097746 is 64779012.

It is a happy number.

It is a super-2 number, since 2×21097746² = 890229772561032, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21097746.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21220 + ... + 22191.

It is an arithmetic number, because the mean of its divisors is an integer number (1975246).

Almost surely, 2^21097746 is an apocalyptic number.

21097746 is an abundant number, since it is smaller than the sum of its proper divisors (26308158).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21097746 is an equidigital number, since it uses as much as digits as its factorization.

21097746 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43428 (or 43416 counting only the distinct ones).

The product of its (nonzero) digits is 21168, while the sum is 36.

The square root of 21097746 is about 4593.2282764957. The cubic root of 21097746 is about 276.3198088696.

The spelling of 21097746 in words is "twenty-one million, ninety-seven thousand, seven hundred forty-six".