21391622 has 8 divisors (see below), whose sum is σ = 36671376. Its totient is φ = 9167832.

The previous prime is 21391621. The next prime is 21391649. The reversal of 21391622 is 22619312.

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

It is a junction number, because it is equal to n+sod(n) for n = 21391591 and 21391600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21391621) 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, 763973 + ... + 764000.

It is an arithmetic number, because the mean of its divisors is an integer number (4583922).

Almost surely, 2^21391622 is an apocalyptic number.

21391622 is a deficient number, since it is larger than the sum of its proper divisors (15279754).

21391622 is a wasteful number, since it uses less digits than its factorization.

21391622 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1527982.

The product of its digits is 1296, while the sum is 26.

The square root of 21391622 is about 4625.1077825279. The cubic root of 21391622 is about 277.5968744371.

The spelling of 21391622 in words is "twenty-one million, three hundred ninety-one thousand, six hundred twenty-two".