21023019 has 6 divisors (see below), whose sum is σ = 30366596. Its totient is φ = 14015340.

The previous prime is 21023017. The next prime is 21023047. The reversal of 21023019 is 91032012.

It is a happy number.

It is not a de Polignac number, because 21023019 - 2¹ = 21023017 is a prime.

It is a super-2 number, since 2×21023019² = 883934655748722, 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 = 21022992 and 21023010.

It is not an unprimeable number, because it can be changed into a prime (21023017) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1167937 + ... + 1167954.

Almost surely, 2^21023019 is an apocalyptic number.

21023019 is a deficient number, since it is larger than the sum of its proper divisors (9343577).

21023019 is a wasteful number, since it uses less digits than its factorization.

21023019 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2335897 (or 2335894 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

The square root of 21023019 is about 4585.0865858782. The cubic root of 21023019 is about 275.9931866623.

The spelling of 21023019 in words is "twenty-one million, twenty-three thousand, nineteen".