21426555 has 16 divisors (see below), whose sum is σ = 34845984. Its totient is φ = 11239680.

The previous prime is 21426553. The next prime is 21426583. The reversal of 21426555 is 55562412.

It is not a de Polignac number, because 21426555 - 2¹ = 21426553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21426553) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10794 + ... + 12623.

It is an arithmetic number, because the mean of its divisors is an integer number (2177874).

Almost surely, 2^21426555 is an apocalyptic number.

21426555 is a deficient number, since it is larger than the sum of its proper divisors (13419429).

21426555 is a wasteful number, since it uses less digits than its factorization.

21426555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23486.

The product of its digits is 12000, while the sum is 30.

The square root of 21426555 is about 4628.8826945603. The cubic root of 21426555 is about 277.7478995716.

Adding to 21426555 its reverse (55562412), we get a palindrome (76988967).

The spelling of 21426555 in words is "twenty-one million, four hundred twenty-six thousand, five hundred fifty-five".