21119687820 has 768 divisors, whose sum is σ = 85279703040. Its totient is φ = 4212864000.

The previous prime is 21119687783. The next prime is 21119687873. The reversal of 21119687820 is 2878691112.

It is a super-2 number, since 2×21119687820² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 197380207 + ... + 197380313.

It is an arithmetic number, because the mean of its divisors is an integer number (111041280).

Almost surely, 2^21119687820 is an apocalyptic number.

21119687820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21119687820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42639851520).

21119687820 is an abundant number, since it is smaller than the sum of its proper divisors (64160015220).

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

21119687820 is a wasteful number, since it uses less digits than its factorization.

21119687820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 291 (or 283 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 45.

The spelling of 21119687820 in words is "twenty-one billion, one hundred nineteen million, six hundred eighty-seven thousand, eight hundred twenty".