21925166555 has 4 divisors (see below), whose sum is σ = 26310199872. Its totient is φ = 17540133240.

The previous prime is 21925166551. The next prime is 21925166561. The reversal of 21925166555 is 55566152912.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21925166555 - 2² = 21925166551 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21925166551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2192516651 + ... + 2192516660.

It is an arithmetic number, because the mean of its divisors is an integer number (6577549968).

Almost surely, 2^21925166555 is an apocalyptic number.

21925166555 is a deficient number, since it is larger than the sum of its proper divisors (4385033317).

21925166555 is an equidigital number, since it uses as much as digits as its factorization.

21925166555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4385033316.

The product of its digits is 810000, while the sum is 47.

The spelling of 21925166555 in words is "twenty-one billion, nine hundred twenty-five million, one hundred sixty-six thousand, five hundred fifty-five".