21229511940 has 960 divisors, whose sum is σ = 89257158144. Its totient is φ = 4096770048.

The previous prime is 21229511879. The next prime is 21229511951. The reversal of 21229511940 is 4911592212.

21229511940 is a `hidden beast` number, since 212 + 295 + 119 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21229511895 and 21229511904.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 319 ways as a sum of consecutive naturals, for example, 107763922 + ... + 107764118.

Almost surely, 2^21229511940 is an apocalyptic number.

21229511940 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 21229511940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44628579072).

21229511940 is an abundant number, since it is smaller than the sum of its proper divisors (68027646204).

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

21229511940 is a wasteful number, since it uses less digits than its factorization.

21229511940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 298 (or 287 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

It can be divided in two parts, 2122951 and 1940, that added together give a triangular number (2124891 = T₂₀₆₁).

The spelling of 21229511940 in words is "twenty-one billion, two hundred twenty-nine million, five hundred eleven thousand, nine hundred forty".