21489842 has 12 divisors (see below), whose sum is σ = 35431998. Its totient is φ = 9768000.

The previous prime is 21489833. The next prime is 21489877. The reversal of 21489842 is 24898412.

It can be written as a sum of positive squares in only one way, i.e., 21446161 + 43681 = 4631^2 + 209^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21489796 and 21489805.

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 5 ways as a sum of consecutive naturals, for example, 44159 + ... + 44642.

Almost surely, 2^21489842 is an apocalyptic number.

21489842 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21489842 is a deficient number, since it is larger than the sum of its proper divisors (13942156).

21489842 is a wasteful number, since it uses less digits than its factorization.

21489842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88825 (or 88814 counting only the distinct ones).

The product of its digits is 36864, while the sum is 38.

The square root of 21489842 is about 4635.7137530266. The cubic root of 21489842 is about 278.0210894409.

The spelling of 21489842 in words is "twenty-one million, four hundred eighty-nine thousand, eight hundred forty-two".