21121211023 has 6 divisors (see below), whose sum is σ = 23215876712. Its totient is φ = 19201100820.

The previous prime is 21121211011. The next prime is 21121211047. The reversal of 21121211023 is 32011212112.

It is not a de Polignac number, because 21121211023 - 2²⁵ = 21087656591 is a prime.

It is a super-2 number, since 2×21121211023² (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 = 21121210988 and 21121211006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121241023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 87277611 + ... + 87277852.

Almost surely, 2^21121211023 is an apocalyptic number.

21121211023 is a deficient number, since it is larger than the sum of its proper divisors (2094665689).

21121211023 is a wasteful number, since it uses less digits than its factorization.

21121211023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174555485 (or 174555474 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 21121211023 its reverse (32011212112), we get a palindrome (53132423135).

The spelling of 21121211023 in words is "twenty-one billion, one hundred twenty-one million, two hundred eleven thousand, twenty-three".