21440131277 has 4 divisors (see below), whose sum is σ = 21486438720. Its totient is φ = 21393823836.

The previous prime is 21440131243. The next prime is 21440131289. The reversal of 21440131277 is 77213104412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21440131277 - 2¹⁰ = 21440130253 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21440131177) 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, 23153027 + ... + 23153952.

It is an arithmetic number, because the mean of its divisors is an integer number (5371609680).

Almost surely, 2^21440131277 is an apocalyptic number.

It is an amenable number.

21440131277 is a deficient number, since it is larger than the sum of its proper divisors (46307443).

21440131277 is an equidigital number, since it uses as much as digits as its factorization.

21440131277 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46307442.

The product of its (nonzero) digits is 9408, while the sum is 32.

Adding to 21440131277 its reverse (77213104412), we get a palindrome (98653235689).

The spelling of 21440131277 in words is "twenty-one billion, four hundred forty million, one hundred thirty-one thousand, two hundred seventy-seven".