21286463778 has 24 divisors (see below), whose sum is σ = 46313654400. Its totient is φ = 7065798264.

The previous prime is 21286463761. The next prime is 21286463801. The reversal of 21286463778 is 87736468212.

It is a super-2 number, since 2×21286463778² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2469718 + ... + 2478321.

It is an arithmetic number, because the mean of its divisors is an integer number (1929735600).

Almost surely, 2^21286463778 is an apocalyptic number.

21286463778 is an abundant number, since it is smaller than the sum of its proper divisors (25027190622).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21286463778 is a wasteful number, since it uses less digits than its factorization.

21286463778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4948286 (or 4948283 counting only the distinct ones).

The product of its digits is 5419008, while the sum is 54.

The spelling of 21286463778 in words is "twenty-one billion, two hundred eighty-six million, four hundred sixty-three thousand, seven hundred seventy-eight".