21534002056 has 32 divisors (see below), whose sum is σ = 46168200000. Its totient is φ = 9224076096.

The previous prime is 21534001991. The next prime is 21534002059. The reversal of 21534002056 is 65020043512.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is not an unprimeable number, because it can be changed into a prime (21534002059) 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, 10495 + ... + 207793.

It is an arithmetic number, because the mean of its divisors is an integer number (1442756250).

Almost surely, 2^21534002056 is an apocalyptic number.

It is an amenable number.

21534002056 is an abundant number, since it is smaller than the sum of its proper divisors (24634197944).

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

21534002056 is a wasteful number, since it uses less digits than its factorization.

21534002056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 199261 (or 199257 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 28.

Adding to 21534002056 its reverse (65020043512), we get a palindrome (86554045568).

The spelling of 21534002056 in words is "twenty-one billion, five hundred thirty-four million, two thousand, fifty-six".