21429936990 has 512 divisors, whose sum is σ = 75432591360. Its totient is φ = 4199040000.

The previous prime is 21429936977. The next prime is 21429936991. The reversal of 21429936990 is 9963992412.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21429936991) by changing a digit.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 26423685 + ... + 26424495.

It is an arithmetic number, because the mean of its divisors is an integer number (147329280).

Almost surely, 2^21429936990 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21429936990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37716295680).

21429936990 is an abundant number, since it is smaller than the sum of its proper divisors (54002654370).

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

21429936990 is a wasteful number, since it uses less digits than its factorization.

21429936990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 917 (or 911 counting only the distinct ones).

The product of its (nonzero) digits is 1889568, while the sum is 54.

The spelling of 21429936990 in words is "twenty-one billion, four hundred twenty-nine million, nine hundred thirty-six thousand, nine hundred ninety".