21013023 has 16 divisors (see below), whose sum is σ = 29196000. Its totient is φ = 13426560.

The previous prime is 21013021. The next prime is 21013043. The reversal of 21013023 is 32031012.

It is a happy number.

It is not a de Polignac number, because 21013023 - 2¹ = 21013021 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21013021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12153 + ... + 13773.

It is an arithmetic number, because the mean of its divisors is an integer number (1824750).

Almost surely, 2^21013023 is an apocalyptic number.

21013023 is a deficient number, since it is larger than the sum of its proper divisors (8182977).

21013023 is a wasteful number, since it uses less digits than its factorization.

21013023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1802.

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 21013023 is about 4583.9964005221. The cubic root of 21013023 is about 275.9494367571.

Adding to 21013023 its reverse (32031012), we get a palindrome (53044035).

The spelling of 21013023 in words is "twenty-one million, thirteen thousand, twenty-three".