21166223560 has 32 divisors (see below), whose sum is σ = 47756692800. Its totient is φ = 8442900160.

The previous prime is 21166223557. The next prime is 21166223563. The reversal of 21166223560 is 6532266112.

It is an interprime number because it is at equal distance from previous prime (21166223557) and next prime (21166223563).

It is not an unprimeable number, because it can be changed into a prime (21166223563) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 722626 + ... + 751345.

It is an arithmetic number, because the mean of its divisors is an integer number (1492396650).

Almost surely, 2^21166223560 is an apocalyptic number.

21166223560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21166223560 is an abundant number, since it is smaller than the sum of its proper divisors (26590469240).

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

21166223560 is a wasteful number, since it uses less digits than its factorization.

21166223560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1474341 (or 1474337 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 34.

Adding to 21166223560 its reverse (6532266112), we get a palindrome (27698489672).

The spelling of 21166223560 in words is "twenty-one billion, one hundred sixty-six million, two hundred twenty-three thousand, five hundred sixty".