21378651467 has 16 divisors (see below), whose sum is σ = 22181955840. Its totient is φ = 20587579488.

The previous prime is 21378651431. The next prime is 21378651479. The reversal of 21378651467 is 76415687312.

It is a cyclic number.

It is not a de Polignac number, because 21378651467 - 2¹² = 21378647371 is a prime.

It is a super-2 number, since 2×21378651467² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (50) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (21378650467) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6439634 + ... + 6442952.

It is an arithmetic number, because the mean of its divisors is an integer number (1386372240).

Almost surely, 2^21378651467 is an apocalyptic number.

21378651467 is a deficient number, since it is larger than the sum of its proper divisors (803304373).

21378651467 is a wasteful number, since it uses less digits than its factorization.

21378651467 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5090.

The product of its digits is 1693440, while the sum is 50.

The spelling of 21378651467 in words is "twenty-one billion, three hundred seventy-eight million, six hundred fifty-one thousand, four hundred sixty-seven".