21155403016 has 128 divisors (see below), whose sum is σ = 46194624000. Its totient is φ = 8982144000.

The previous prime is 21155403001. The next prime is 21155403023. The reversal of 21155403016 is 61030455112.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 52756416 + ... + 52756816.

It is an arithmetic number, because the mean of its divisors is an integer number (360895500).

Almost surely, 2^21155403016 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21155403016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23097312000).

21155403016 is an abundant number, since it is smaller than the sum of its proper divisors (25039220984).

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

21155403016 is a wasteful number, since it uses less digits than its factorization.

21155403016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 803 (or 799 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 28.

Adding to 21155403016 its reverse (61030455112), we get a palindrome (82185858128).

The spelling of 21155403016 in words is "twenty-one billion, one hundred fifty-five million, four hundred three thousand, sixteen".