21010221023 has 4 divisors (see below), whose sum is σ = 22920241128. Its totient is φ = 19100200920.

The previous prime is 21010220999. The next prime is 21010221053. The reversal of 21010221023 is 32012201012.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21010221023 - 2²⁰ = 21009172447 is a prime.

It is a super-2 number, since 2×21010221023² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21010220989 and 21010221007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010221053) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 955010036 + ... + 955010057.

It is an arithmetic number, because the mean of its divisors is an integer number (5730060282).

Almost surely, 2^21010221023 is an apocalyptic number.

21010221023 is a deficient number, since it is larger than the sum of its proper divisors (1910020105).

21010221023 is a wasteful number, since it uses less digits than its factorization.

21010221023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1910020104.

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 21010221023 its reverse (32012201012), we get a palindrome (53022422035).

The spelling of 21010221023 in words is "twenty-one billion, ten million, two hundred twenty-one thousand, twenty-three".