21214036501261 has 4 divisors (see below), whose sum is σ = 21731452025724. Its totient is φ = 20696620976800.

The previous prime is 21214036501237. The next prime is 21214036501267. The reversal of 21214036501261 is 16210563041212.

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 2486910076036 + 18727126425225 = 1576994^2 + 4327485^2 .

It is a cyclic number.

It is not a de Polignac number, because 21214036501261 - 2¹¹ = 21214036499213 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 (21214036501267) 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, 258707762170 + ... + 258707762251.

It is an arithmetic number, because the mean of its divisors is an integer number (5432863006431).

Almost surely, 2^{21214036501261} is an apocalyptic number.

It is an amenable number.

21214036501261 is a deficient number, since it is larger than the sum of its proper divisors (517415524463).

21214036501261 is an equidigital number, since it uses as much as digits as its factorization.

21214036501261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 517415524462.

The product of its (nonzero) digits is 17280, while the sum is 34.

Adding to 21214036501261 its reverse (16210563041212), we get a palindrome (37424599542473).

The spelling of 21214036501261 in words is "twenty-one trillion, two hundred fourteen billion, thirty-six million, five hundred one thousand, two hundred sixty-one".