263121010421 has 4 divisors (see below), whose sum is σ = 265449515052. Its totient is φ = 260792505792.

The previous prime is 263121010349. The next prime is 263121010423. The reversal of 263121010421 is 124010121362.

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

It can be written as a sum of positive squares in 2 ways, for example, as 74731156900 + 188389853521 = 273370^2 + 434039^2 .

It is a cyclic number.

It is not a de Polignac number, because 263121010421 - 2¹⁸ = 263120748277 is a prime.

It is a super-2 number, since 2×263121010421² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (263121010423) 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, 1164252146 + ... + 1164252371.

It is an arithmetic number, because the mean of its divisors is an integer number (66362378763).

Almost surely, 2^263121010421 is an apocalyptic number.

It is an amenable number.

263121010421 is a deficient number, since it is larger than the sum of its proper divisors (2328504631).

263121010421 is a wasteful number, since it uses less digits than its factorization.

263121010421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2328504630.

The product of its (nonzero) digits is 576, while the sum is 23.

Adding to 263121010421 its reverse (124010121362), we get a palindrome (387131131783).

The spelling of 263121010421 in words is "two hundred sixty-three billion, one hundred twenty-one million, ten thousand, four hundred twenty-one".