21011221098 has 64 divisors (see below), whose sum is σ = 56170368000. Its totient is φ = 5687245872.

The previous prime is 21011221097. The next prime is 21011221129. The reversal of 21011221098 is 89012211012.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21011221097) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1455588 + ... + 1469951.

It is an arithmetic number, because the mean of its divisors is an integer number (877662000).

Almost surely, 2^21011221098 is an apocalyptic number.

21011221098 is an abundant number, since it is smaller than the sum of its proper divisors (35159146902).

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

21011221098 is a wasteful number, since it uses less digits than its factorization.

21011221098 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2925576 (or 2925570 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 27.

The spelling of 21011221098 in words is "twenty-one billion, eleven million, two hundred twenty-one thousand, ninety-eight".