21506065357420 has 48 divisors (see below), whose sum is σ = 53009544893760. Its totient is φ = 7174224117504.

The previous prime is 21506065357373. The next prime is 21506065357477. The reversal of 21506065357420 is 2475356060512.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2075869855 + ... + 2075880214.

It is an arithmetic number, because the mean of its divisors is an integer number (1104365518620).

Almost surely, 2^{21506065357420} is an apocalyptic number.

21506065357420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21506065357420 is an abundant number, since it is smaller than the sum of its proper divisors (31503479536340).

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

21506065357420 is a wasteful number, since it uses less digits than its factorization.

21506065357420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4151750122 (or 4151750120 counting only the distinct ones).

The product of its (nonzero) digits is 1512000, while the sum is 46.

The spelling of 21506065357420 in words is "twenty-one trillion, five hundred six billion, sixty-five million, three hundred fifty-seven thousand, four hundred twenty".