21012122023 has 4 divisors (see below), whose sum is σ = 21086370088. Its totient is φ = 20937873960.

The previous prime is 21012122003. The next prime is 21012122041. The reversal of 21012122023 is 32022121012.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21012122023 is a prime.

It is a super-2 number, since 2×21012122023² (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 = 21012121988 and 21012122006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012122003) 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, 37123608 + ... + 37124173.

It is an arithmetic number, because the mean of its divisors is an integer number (5271592522).

Almost surely, 2^21012122023 is an apocalyptic number.

21012122023 is a deficient number, since it is larger than the sum of its proper divisors (74248065).

21012122023 is an equidigital number, since it uses as much as digits as its factorization.

21012122023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74248064.

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21012122023 its reverse (32022121012), we get a palindrome (53034243035).

The spelling of 21012122023 in words is "twenty-one billion, twelve million, one hundred twenty-two thousand, twenty-three".