21240501 has 8 divisors (see below), whose sum is σ = 29011584. Its totient is φ = 13814880.

The previous prime is 21240433. The next prime is 21240511. The reversal of 21240501 is 10504212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21240501 - 2¹⁵ = 21207733 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21240511) 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 7 ways as a sum of consecutive naturals, for example, 86221 + ... + 86466.

It is an arithmetic number, because the mean of its divisors is an integer number (3626448).

Almost surely, 2^21240501 is an apocalyptic number.

It is an amenable number.

21240501 is a deficient number, since it is larger than the sum of its proper divisors (7771083).

21240501 is a wasteful number, since it uses less digits than its factorization.

21240501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172731.

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 21240501 is about 4608.7418022710. The cubic root of 21240501 is about 276.9416351464.

Adding to 21240501 its reverse (10504212), we get a palindrome (31744713).

The spelling of 21240501 in words is "twenty-one million, two hundred forty thousand, five hundred one".