21429951840 has 384 divisors, whose sum is σ = 82521815040. Its totient is φ = 5193745920.

The previous prime is 21429951821. The next prime is 21429951871. The reversal of 21429951840 is 4815992412.

It is a happy number.

21429951840 is a `hidden beast` number, since 2 + 1 + 4 + 2 + 99 + 518 + 40 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 5748057 + ... + 5751783.

It is an arithmetic number, because the mean of its divisors is an integer number (214900560).

Almost surely, 2^21429951840 is an apocalyptic number.

21429951840 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 21429951840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41260907520).

21429951840 is an abundant number, since it is smaller than the sum of its proper divisors (61091863200).

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

21429951840 is a wasteful number, since it uses less digits than its factorization.

21429951840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3784 (or 3748 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 45.

The spelling of 21429951840 in words is "twenty-one billion, four hundred twenty-nine million, nine hundred fifty-one thousand, eight hundred forty".