21212279040 has 288 divisors, whose sum is σ = 73097168256. Its totient is φ = 5222563840.

The previous prime is 21212279029. The next prime is 21212279047. The reversal of 21212279040 is 4097221212.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 21212278989 and 21212279007.

It is not an unprimeable number, because it can be changed into a prime (21212279047) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 3456775 + ... + 3462905.

It is an arithmetic number, because the mean of its divisors is an integer number (253809612).

Almost surely, 2^21212279040 is an apocalyptic number.

21212279040 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 21212279040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36548584128).

21212279040 is an abundant number, since it is smaller than the sum of its proper divisors (51884889216).

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

21212279040 is a wasteful number, since it uses less digits than its factorization.

21212279040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6225 (or 6211 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 30.

The spelling of 21212279040 in words is "twenty-one billion, two hundred twelve million, two hundred seventy-nine thousand, forty".