21622387 has 4 divisors (see below), whose sum is σ = 21671640. Its totient is φ = 21573136.

The previous prime is 21622339. The next prime is 21622417. The reversal of 21622387 is 78322612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21622387 - 2⁷ = 21622259 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21622327) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23962 + ... + 24847.

It is an arithmetic number, because the mean of its divisors is an integer number (5417910).

Almost surely, 2^21622387 is an apocalyptic number.

21622387 is a deficient number, since it is larger than the sum of its proper divisors (49253).

21622387 is an equidigital number, since it uses as much as digits as its factorization.

21622387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49252.

The product of its digits is 8064, while the sum is 31.

The square root of 21622387 is about 4649.9878494465. The cubic root of 21622387 is about 278.5915109156.

Adding to 21622387 its reverse (78322612), we get a palindrome (99944999).

The spelling of 21622387 in words is "twenty-one million, six hundred twenty-two thousand, three hundred eighty-seven".