21512043 has 12 divisors (see below), whose sum is σ = 35512048. Its totient is φ = 12292560.

The previous prime is 21512033. The next prime is 21512053. The reversal of 21512043 is 34021512.

It is an interprime number because it is at equal distance from previous prime (21512033) and next prime (21512053).

It is not a de Polignac number, because 21512043 - 2⁴ = 21512027 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21512033) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 170668 + ... + 170793.

Almost surely, 2^21512043 is an apocalyptic number.

21512043 is a deficient number, since it is larger than the sum of its proper divisors (14000005).

21512043 is a wasteful number, since it uses less digits than its factorization.

21512043 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 341474 (or 341471 counting only the distinct ones).

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

The square root of 21512043 is about 4638.1076960329. The cubic root of 21512043 is about 278.1167970143.

Adding to 21512043 its reverse (34021512), we get a palindrome (55533555).

The spelling of 21512043 in words is "twenty-one million, five hundred twelve thousand, forty-three".