21496973 has 6 divisors (see below), whose sum is σ = 22472814. Its totient is φ = 20561816.

The previous prime is 21496957. The next prime is 21496991. The reversal of 21496973 is 37969412.

It can be written as a sum of positive squares in only one way, i.e., 11276164 + 10220809 = 3358^2 + 3197^2 .

It is not a de Polignac number, because 21496973 - 2⁴ = 21496957 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21496973.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21496903) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 19790 + ... + 20847.

It is an arithmetic number, because the mean of its divisors is an integer number (3745469).

Almost surely, 2^21496973 is an apocalyptic number.

21496973 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21496973 is a deficient number, since it is larger than the sum of its proper divisors (975841).

21496973 is an equidigital number, since it uses as much as digits as its factorization.

21496973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40683 (or 40660 counting only the distinct ones).

The product of its digits is 81648, while the sum is 41.

The square root of 21496973 is about 4636.4828264537. The cubic root of 21496973 is about 278.0518380637.

The spelling of 21496973 in words is "twenty-one million, four hundred ninety-six thousand, nine hundred seventy-three".