21372387 has 8 divisors (see below), whose sum is σ = 28963920. Its totient is φ = 14014560.

The previous prime is 21372367. The next prime is 21372413. The reversal of 21372387 is 78327312.

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

It is not a de Polignac number, because 21372387 - 2¹¹ = 21370339 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21372317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 58212 + ... + 58577.

It is an arithmetic number, because the mean of its divisors is an integer number (3620490).

Almost surely, 2^21372387 is an apocalyptic number.

21372387 is a deficient number, since it is larger than the sum of its proper divisors (7591533).

21372387 is a wasteful number, since it uses less digits than its factorization.

21372387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116853.

The product of its digits is 14112, while the sum is 33.

The square root of 21372387 is about 4623.0279038743. The cubic root of 21372387 is about 277.5136459485.

Adding to 21372387 its reverse (78327312), we get a palindrome (99699699).

The spelling of 21372387 in words is "twenty-one million, three hundred seventy-two thousand, three hundred eighty-seven".