21363172 has 6 divisors (see below), whose sum is σ = 37385558. Its totient is φ = 10681584.

The previous prime is 21363161. The next prime is 21363179. The reversal of 21363172 is 27136312.

It can be written as a sum of positive squares in only one way, i.e., 21031396 + 331776 = 4586^2 + 576^2 .

It is not an unprimeable number, because it can be changed into a prime (21363179) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2670393 + ... + 2670400.

Almost surely, 2^21363172 is an apocalyptic number.

It is an amenable number.

21363172 is a deficient number, since it is larger than the sum of its proper divisors (16022386).

21363172 is a wasteful number, since it uses less digits than its factorization.

21363172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5340797 (or 5340795 counting only the distinct ones).

The product of its digits is 1512, while the sum is 25.

The square root of 21363172 is about 4622.0311552390. The cubic root of 21363172 is about 277.4737556004.

Adding to 21363172 its reverse (27136312), we get a palindrome (48499484).

The spelling of 21363172 in words is "twenty-one million, three hundred sixty-three thousand, one hundred seventy-two".