21278000416 has 24 divisors (see below), whose sum is σ = 42024920364. Its totient is φ = 10605004800.

The previous prime is 21278000407. The next prime is 21278000423. The reversal of 21278000416 is 61400087212.

It can be written as a sum of positive squares in 2 ways, for example, as 16743324816 + 4534675600 = 129396^2 + 67340^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1052185 + ... + 1072216.

Almost surely, 2^21278000416 is an apocalyptic number.

It is an amenable number.

21278000416 is a deficient number, since it is larger than the sum of its proper divisors (20746919948).

21278000416 is a wasteful number, since it uses less digits than its factorization.

21278000416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2124724 (or 2124716 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 31.

Adding to 21278000416 its reverse (61400087212), we get a palindrome (82678087628).

The spelling of 21278000416 in words is "twenty-one billion, two hundred seventy-eight million, four hundred sixteen", and thus it is an aban number.