21581434050 has 96 divisors (see below), whose sum is σ = 61460709120. Its totient is φ = 4956494400.

The previous prime is 21581434019. The next prime is 21581434051. The reversal of 21581434050 is 5043418512.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (21581434051) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 312852 + ... + 375551.

It is an arithmetic number, because the mean of its divisors is an integer number (640215720).

Almost surely, 2^21581434050 is an apocalyptic number.

21581434050 is an abundant number, since it is smaller than the sum of its proper divisors (39879275070).

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

21581434050 is a wasteful number, since it uses less digits than its factorization.

21581434050 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 688448 (or 688443 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 33.

The spelling of 21581434050 in words is "twenty-one billion, five hundred eighty-one million, four hundred thirty-four thousand, fifty".