21371387 has 8 divisors (see below), whose sum is σ = 21930480. Its totient is φ = 20815200.

The previous prime is 21371377. The next prime is 21371401. The reversal of 21371387 is 78317312.

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

It is a cyclic number.

It is not a de Polignac number, because 21371387 - 2¹⁴ = 21355003 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21371377) 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, 29789 + ... + 30497.

It is an arithmetic number, because the mean of its divisors is an integer number (2741310).

Almost surely, 2^21371387 is an apocalyptic number.

21371387 is a deficient number, since it is larger than the sum of its proper divisors (559093).

21371387 is an equidigital number, since it uses as much as digits as its factorization.

21371387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1453.

The product of its digits is 7056, while the sum is 32.

The square root of 21371387 is about 4622.9197483841. The cubic root of 21371387 is about 277.5093176538.

Adding to 21371387 its reverse (78317312), we get a palindrome (99688699).

The spelling of 21371387 in words is "twenty-one million, three hundred seventy-one thousand, three hundred eighty-seven".