21125043 has 40 divisors (see below), whose sum is σ = 33454080. Its totient is φ = 13264560.

The previous prime is 21125029. The next prime is 21125057. The reversal of 21125043 is 34052112.

It is an interprime number because it is at equal distance from previous prime (21125029) and next prime (21125057).

It is not a de Polignac number, because 21125043 - 2¹² = 21120947 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21125003) 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 39 ways as a sum of consecutive naturals, for example, 117928 + ... + 118106.

It is an arithmetic number, because the mean of its divisors is an integer number (836352).

Almost surely, 2^21125043 is an apocalyptic number.

21125043 is a deficient number, since it is larger than the sum of its proper divisors (12329037).

21125043 is a wasteful number, since it uses less digits than its factorization.

21125043 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 269 (or 260 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21125043 is about 4596.1987554935. The cubic root of 21125043 is about 276.4389282478.

Adding to 21125043 its reverse (34052112), we get a palindrome (55177155).

The spelling of 21125043 in words is "twenty-one million, one hundred twenty-five thousand, forty-three".