21405098 has 16 divisors (see below), whose sum is σ = 37721376. Its totient is φ = 8981040.

The previous prime is 21405067. The next prime is 21405113. The reversal of 21405098 is 89050412.

It is a self number, because there is not a number n which added to its sum of digits gives 21405098.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37136 + ... + 37707.

It is an arithmetic number, because the mean of its divisors is an integer number (2357586).

Almost surely, 2^21405098 is an apocalyptic number.

21405098 is a deficient number, since it is larger than the sum of its proper divisors (16316278).

21405098 is a wasteful number, since it uses less digits than its factorization.

21405098 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74869.

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 21405098 is about 4626.5643840759. The cubic root of 21405098 is about 277.6551544218.

It can be divided in two parts, 21 and 405098, that multiplied together give a palindrome (8507058).

The spelling of 21405098 in words is "twenty-one million, four hundred five thousand, ninety-eight".