21427355 has 8 divisors (see below), whose sum is σ = 26542464. Its totient is φ = 16588800.

The previous prime is 21427349. The next prime is 21427369. The reversal of 21427355 is 55372412.

It is a happy number.

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

It is not a de Polignac number, because 21427355 - 2⁴ = 21427339 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 68966 + ... + 69275.

It is an arithmetic number, because the mean of its divisors is an integer number (3317808).

Almost surely, 2^21427355 is an apocalyptic number.

21427355 is a deficient number, since it is larger than the sum of its proper divisors (5115109).

21427355 is a wasteful number, since it uses less digits than its factorization.

21427355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138277.

The product of its digits is 8400, while the sum is 29.

The square root of 21427355 is about 4628.9691076956. The cubic root of 21427355 is about 277.7513562721.

Adding to 21427355 its reverse (55372412), we get a palindrome (76799767).

The spelling of 21427355 in words is "twenty-one million, four hundred twenty-seven thousand, three hundred fifty-five".