21097218240 has 336 divisors, whose sum is σ = 83381575680. Its totient is φ = 4796098560.

The previous prime is 21097218239. The next prime is 21097218251. The reversal of 21097218240 is 4281279012.

It is a tau number, because it is divible by the number of its divisors (336).

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 = 21097218195 and 21097218204.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3847821 + ... + 3853299.

Almost surely, 2^21097218240 is an apocalyptic number.

21097218240 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 21097218240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41690787840).

21097218240 is an abundant number, since it is smaller than the sum of its proper divisors (62284357440).

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

21097218240 is a wasteful number, since it uses less digits than its factorization.

21097218240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5700 (or 5687 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The spelling of 21097218240 in words is "twenty-one billion, ninety-seven million, two hundred eighteen thousand, two hundred forty".