21778651275 has 48 divisors (see below), whose sum is σ = 37272614400. Its totient is φ = 11207647360.

The previous prime is 21778651259. The next prime is 21778651277. The reversal of 21778651275 is 57215687712.

It is not a de Polignac number, because 21778651275 - 2⁴ = 21778651259 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21778651277) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 6390622 + ... + 6394028.

It is an arithmetic number, because the mean of its divisors is an integer number (776512800).

Almost surely, 2^21778651275 is an apocalyptic number.

21778651275 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21778651275 is a deficient number, since it is larger than the sum of its proper divisors (15493963125).

21778651275 is a wasteful number, since it uses less digits than its factorization.

21778651275 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6388 (or 6383 counting only the distinct ones).

The product of its digits is 1646400, while the sum is 51.

The spelling of 21778651275 in words is "twenty-one billion, seven hundred seventy-eight million, six hundred fifty-one thousand, two hundred seventy-five".