21778220970 has 48 divisors (see below), whose sum is σ = 61770956832. Its totient is φ = 5279568480.

The previous prime is 21778220963. The next prime is 21778220977. The reversal of 21778220970 is 7902287712.

It is an interprime number because it is at equal distance from previous prime (21778220963) and next prime (21778220977).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21778220977) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10998112 + ... + 11000091.

It is an arithmetic number, because the mean of its divisors is an integer number (1286894934).

Almost surely, 2^21778220970 is an apocalyptic number.

21778220970 is an abundant number, since it is smaller than the sum of its proper divisors (39992735862).

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

21778220970 is a wasteful number, since it uses less digits than its factorization.

21778220970 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21998227 (or 21998224 counting only the distinct ones).

The product of its (nonzero) digits is 197568, while the sum is 45.

The spelling of 21778220970 in words is "twenty-one billion, seven hundred seventy-eight million, two hundred twenty thousand, nine hundred seventy".