21278348573 has 2 divisors, whose sum is σ = 21278348574. Its totient is φ = 21278348572.

The previous prime is 21278348569. The next prime is 21278348659. The reversal of 21278348573 is 37584387212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12193018084 + 9085330489 = 110422^2 + 95317^2 .

It is a cyclic number.

It is not a de Polignac number, because 21278348573 - 2² = 21278348569 is a prime.

It is a super-2 number, since 2×21278348573² (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 (21278348513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10639174286 + 10639174287.

It is an arithmetic number, because the mean of its divisors is an integer number (10639174287).

Almost surely, 2^21278348573 is an apocalyptic number.

It is an amenable number.

21278348573 is a deficient number, since it is larger than the sum of its proper divisors (1).

21278348573 is an equidigital number, since it uses as much as digits as its factorization.

21278348573 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2257920, while the sum is 50.

The spelling of 21278348573 in words is "twenty-one billion, two hundred seventy-eight million, three hundred forty-eight thousand, five hundred seventy-three".