21401434560 has 168 divisors, whose sum is σ = 74688758928. Its totient is φ = 5188198400.

The previous prime is 21401434559. The next prime is 21401434597. The reversal of 21401434560 is 6543410412.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 24040 + ... + 208280.

It is an arithmetic number, because the mean of its divisors is an integer number (444575946).

Almost surely, 2^21401434560 is an apocalyptic number.

21401434560 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 21401434560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37344379464).

21401434560 is an abundant number, since it is smaller than the sum of its proper divisors (53287324368).

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

21401434560 is a wasteful number, since it uses less digits than its factorization.

21401434560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 184283 (or 184262 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 30.

Adding to 21401434560 its reverse (6543410412), we get a palindrome (27944844972).

The spelling of 21401434560 in words is "twenty-one billion, four hundred one million, four hundred thirty-four thousand, five hundred sixty".