21439042560 has 396 divisors, whose sum is σ = 80468790012. Its totient is φ = 5275385856.

The previous prime is 21439042549. The next prime is 21439042631. The reversal of 21439042560 is 6524093412.

It is a happy number.

21439042560 is a `hidden beast` number, since 2 + 1 + 4 + 3 + 90 + 4 + 2 + 560 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 868598784 + 20570443776 = 29472^2 + 143424^2 .

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 7786144 + ... + 7788896.

Almost surely, 2^21439042560 is an apocalyptic number.

21439042560 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 21439042560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40234395006).

21439042560 is an abundant number, since it is smaller than the sum of its proper divisors (59029747452).

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

21439042560 is a wasteful number, since it uses less digits than its factorization.

21439042560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2810 (or 2776 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The spelling of 21439042560 in words is "twenty-one billion, four hundred thirty-nine million, forty-two thousand, five hundred sixty".