21168953 has 4 divisors (see below), whose sum is σ = 22797348. Its totient is φ = 19540560.

The previous prime is 21168949. The next prime is 21168967. The reversal of 21168953 is 35986112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9314704 + 11854249 = 3052^2 + 3443^2 .

It is not a de Polignac number, because 21168953 - 2² = 21168949 is a prime.

It is a super-2 number, since 2×21168953² = 896249142232418, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21168923) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 814178 + ... + 814203.

It is an arithmetic number, because the mean of its divisors is an integer number (5699337).

Almost surely, 2^21168953 is an apocalyptic number.

It is an amenable number.

21168953 is a deficient number, since it is larger than the sum of its proper divisors (1628395).

21168953 is a wasteful number, since it uses less digits than its factorization.

21168953 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1628394.

The product of its digits is 12960, while the sum is 35.

The square root of 21168953 is about 4600.9730492582. The cubic root of 21168953 is about 276.6303287705.

The spelling of 21168953 in words is "twenty-one million, one hundred sixty-eight thousand, nine hundred fifty-three".