21485123 has 12 divisors (see below), whose sum is σ = 24259200. Its totient is φ = 19000080.

The previous prime is 21485119. The next prime is 21485129. The reversal of 21485123 is 32158412.

It is not a de Polignac number, because 21485123 - 2² = 21485119 is a prime.

It is a super-2 number, since 2×21485123² = 923221020650258, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21485092 and 21485101.

It is not an unprimeable number, because it can be changed into a prime (21485129) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 2078 + ... + 6876.

It is an arithmetic number, because the mean of its divisors is an integer number (2021600).

Almost surely, 2^21485123 is an apocalyptic number.

21485123 is a deficient number, since it is larger than the sum of its proper divisors (2774077).

21485123 is a wasteful number, since it uses less digits than its factorization.

21485123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4858 (or 4847 counting only the distinct ones).

The product of its digits is 1920, while the sum is 26.

The square root of 21485123 is about 4635.2047419720. The cubic root of 21485123 is about 278.0007375375. Note that the first 3 decimals are identical.

Subtracting 21485123 from its reverse (32158412), we obtain a square (10673289 = 3267²).

The spelling of 21485123 in words is "twenty-one million, four hundred eighty-five thousand, one hundred twenty-three".