21278632877 has 2 divisors, whose sum is σ = 21278632878. Its totient is φ = 21278632876.

The previous prime is 21278632871. The next prime is 21278632883. The reversal of 21278632877 is 77823687212.

It is a balanced prime because it is at equal distance from previous prime (21278632871) and next prime (21278632883).

It can be written as a sum of positive squares in only one way, i.e., 12537504841 + 8741128036 = 111971^2 + 93494^2 .

It is a cyclic number.

It is not a de Polignac number, because 21278632877 - 2²⁸ = 21010197421 is a prime.

It is a super-2 number, since 2×21278632877² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21278632871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10639316438 + 10639316439.

It is an arithmetic number, because the mean of its divisors is an integer number (10639316439).

Almost surely, 2^21278632877 is an apocalyptic number.

It is an amenable number.

21278632877 is a deficient number, since it is larger than the sum of its proper divisors (1).

21278632877 is an equidigital number, since it uses as much as digits as its factorization.

21278632877 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3161088, while the sum is 53.

The spelling of 21278632877 in words is "twenty-one billion, two hundred seventy-eight million, six hundred thirty-two thousand, eight hundred seventy-seven".