21135545340 has 288 divisors, whose sum is σ = 74914426944. Its totient is φ = 4412620800.

The previous prime is 21135545323. The next prime is 21135545357. The reversal of 21135545340 is 4354553112.

It is an interprime number because it is at equal distance from previous prime (21135545323) and next prime (21135545357).

It is a super-2 number, since 2×21135545340² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 3704490 + ... + 3710190.

It is an arithmetic number, because the mean of its divisors is an integer number (260119538).

Almost surely, 2^21135545340 is an apocalyptic number.

21135545340 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 21135545340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37457213472).

21135545340 is an abundant number, since it is smaller than the sum of its proper divisors (53778881604).

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

21135545340 is a wasteful number, since it uses less digits than its factorization.

21135545340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5837 (or 5828 counting only the distinct ones).

The product of its (nonzero) digits is 36000, while the sum is 33.

The spelling of 21135545340 in words is "twenty-one billion, one hundred thirty-five million, five hundred forty-five thousand, three hundred forty".