21276212557 has 2 divisors, whose sum is σ = 21276212558. Its totient is φ = 21276212556.

The previous prime is 21276212543. The next prime is 21276212603. The reversal of 21276212557 is 75521267212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18275254596 + 3000957961 = 135186^2 + 54781^2 .

It is a cyclic number.

It is not a de Polignac number, because 21276212557 - 2¹¹ = 21276210509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21276282557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10638106278 + 10638106279.

It is an arithmetic number, because the mean of its divisors is an integer number (10638106279).

Almost surely, 2^21276212557 is an apocalyptic number.

It is an amenable number.

21276212557 is a deficient number, since it is larger than the sum of its proper divisors (1).

21276212557 is an equidigital number, since it uses as much as digits as its factorization.

21276212557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 117600, while the sum is 40.

Adding to 21276212557 its reverse (75521267212), we get a palindrome (96797479769).

The spelling of 21276212557 in words is "twenty-one billion, two hundred seventy-six million, two hundred twelve thousand, five hundred fifty-seven".