21946438825 has 12 divisors (see below), whose sum is σ = 27215830620. Its totient is φ = 17555701760.

The previous prime is 21946438823. The next prime is 21946438831. The reversal of 21946438825 is 52883464912.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 897361936 + 21049076889 = 29956^2 + 145083^2 .

It is not a de Polignac number, because 21946438825 - 2¹ = 21946438823 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21946438823) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 355881 + ... + 412969.

It is an arithmetic number, because the mean of its divisors is an integer number (2267985885).

Almost surely, 2^21946438825 is an apocalyptic number.

21946438825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21946438825 is a deficient number, since it is larger than the sum of its proper divisors (5269391795).

21946438825 is a wasteful number, since it uses less digits than its factorization.

21946438825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72476 (or 72471 counting only the distinct ones).

The product of its digits is 3317760, while the sum is 52.

The spelling of 21946438825 in words is "twenty-one billion, nine hundred forty-six million, four hundred thirty-eight thousand, eight hundred twenty-five".