21121001361023 has 16 divisors (see below), whose sum is σ = 22255784778240. Its totient is φ = 20004302027424.

The previous prime is 21121001360989. The next prime is 21121001361167. The reversal of 21121001361023 is 32016310012112.

It is a cyclic number.

It is not a de Polignac number, because 21121001361023 - 2¹⁰ = 21121001359999 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21121001361023.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121001369023) 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, 20735993 + ... + 21730701.

It is an arithmetic number, because the mean of its divisors is an integer number (1390986548640).

Almost surely, 2^{21121001361023} is an apocalyptic number.

21121001361023 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21121001361023 is a deficient number, since it is larger than the sum of its proper divisors (1134783417217).

21121001361023 is a wasteful number, since it uses less digits than its factorization.

21121001361023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1003798.

The product of its (nonzero) digits is 432, while the sum is 23.

Adding to 21121001361023 its reverse (32016310012112), we get a palindrome (53137311373135).

The spelling of 21121001361023 in words is "twenty-one trillion, one hundred twenty-one billion, one million, three hundred sixty-one thousand, twenty-three".