21263172 has 24 divisors (see below), whose sum is σ = 56702016. Its totient is φ = 6075168.

The previous prime is 21263171. The next prime is 21263173. The reversal of 21263172 is 27136212.

It is an interprime number because it is at equal distance from previous prime (21263171) and next prime (21263173).

It is a nude number because it is divisible by every one of its digits.

It is a zygodrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (21263171) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 126483 + ... + 126650.

It is an arithmetic number, because the mean of its divisors is an integer number (2362584).

Almost surely, 2^21263172 is an apocalyptic number.

It is an amenable number.

21263172 is an abundant number, since it is smaller than the sum of its proper divisors (35438844).

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

21263172 is a wasteful number, since it uses less digits than its factorization.

21263172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 253147 (or 253145 counting only the distinct ones).

The product of its digits is 1008, while the sum is 24.

The square root of 21263172 is about 4611.2007113115. The cubic root of 21263172 is about 277.0401311178.

Adding to 21263172 its reverse (27136212), we get a palindrome (48399384).

The spelling of 21263172 in words is "twenty-one million, two hundred sixty-three thousand, one hundred seventy-two".