21169973 has 4 divisors (see below), whose sum is σ = 23094528. Its totient is φ = 19245420.

The previous prime is 21169969. The next prime is 21169979. The reversal of 21169973 is 37996112.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21169973 - 2² = 21169969 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21169979) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 962261 + ... + 962282.

It is an arithmetic number, because the mean of its divisors is an integer number (5773632).

Almost surely, 2^21169973 is an apocalyptic number.

It is an amenable number.

21169973 is a deficient number, since it is larger than the sum of its proper divisors (1924555).

21169973 is a wasteful number, since it uses less digits than its factorization.

21169973 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1924554.

The product of its digits is 20412, while the sum is 38.

The square root of 21169973 is about 4601.0838940406. The cubic root of 21169973 is about 276.6347717300.

The spelling of 21169973 in words is "twenty-one million, one hundred sixty-nine thousand, nine hundred seventy-three".