21901173 has 16 divisors (see below), whose sum is σ = 33505920. Its totient is φ = 12465216.

The previous prime is 21901171. The next prime is 21901183. The reversal of 21901173 is 37110912.

It is not a de Polignac number, because 21901173 - 2¹ = 21901171 is a prime.

It is a super-2 number, since 2×21901173² = 959322757551858, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21901171) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3711 + ... + 7587.

It is an arithmetic number, because the mean of its divisors is an integer number (2094120).

Almost surely, 2^21901173 is an apocalyptic number.

It is an amenable number.

21901173 is a deficient number, since it is larger than the sum of its proper divisors (11604747).

21901173 is a wasteful number, since it uses less digits than its factorization.

21901173 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4156.

The product of its (nonzero) digits is 378, while the sum is 24.

The square root of 21901173 is about 4679.8689084204. The cubic root of 21901173 is about 279.7837318099.

It can be divided in two parts, 21901 and 173, that multiplied together give a palindrome (3788873).

The spelling of 21901173 in words is "twenty-one million, nine hundred one thousand, one hundred seventy-three".