21354455 has 4 divisors (see below), whose sum is σ = 25625352. Its totient is φ = 17083560.

The previous prime is 21354451. The next prime is 21354551. The reversal of 21354455 is 55445312.

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

It is not a de Polignac number, because 21354455 - 2² = 21354451 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21354451) 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, 2135441 + ... + 2135450.

It is an arithmetic number, because the mean of its divisors is an integer number (6406338).

Almost surely, 2^21354455 is an apocalyptic number.

21354455 is a deficient number, since it is larger than the sum of its proper divisors (4270897).

21354455 is an equidigital number, since it uses as much as digits as its factorization.

21354455 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4270896.

The product of its digits is 12000, while the sum is 29.

The square root of 21354455 is about 4621.0880753346. The cubic root of 21354455 is about 277.4360104600.

Adding to 21354455 its reverse (55445312), we get a palindrome (76799767).

The spelling of 21354455 in words is "twenty-one million, three hundred fifty-four thousand, four hundred fifty-five".