21936651828 has 288 divisors, whose sum is σ = 68288984064. Its totient is φ = 5413588992.

The previous prime is 21936651809. The next prime is 21936651839. The reversal of 21936651828 is 82815663912.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 28978026 + ... + 28978782.

It is an arithmetic number, because the mean of its divisors is an integer number (237114528).

Almost surely, 2^21936651828 is an apocalyptic number.

21936651828 is a gapful number since it is divisible by the number (28) 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 21936651828, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34144492032).

21936651828 is an abundant number, since it is smaller than the sum of its proper divisors (46352332236).

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

21936651828 is a wasteful number, since it uses less digits than its factorization.

21936651828 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1031 (or 1022 counting only the distinct ones).

The product of its digits is 1244160, while the sum is 51.

The spelling of 21936651828 in words is "twenty-one billion, nine hundred thirty-six million, six hundred fifty-one thousand, eight hundred twenty-eight".