21420351415601 has 4 divisors (see below), whose sum is σ = 21473768751204. Its totient is φ = 21366934080000.

The previous prime is 21420351415591. The next prime is 21420351415699. The reversal of 21420351415601 is 10651415302412.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 21318526605601 + 101824810000 = 4617199^2 + 319100^2 .

It is a cyclic number.

It is not a de Polignac number, because 21420351415601 - 2¹⁸ = 21420351153457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21420351415201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26708667200 + ... + 26708668001.

It is an arithmetic number, because the mean of its divisors is an integer number (5368442187801).

Almost surely, 2^{21420351415601} is an apocalyptic number.

It is an amenable number.

21420351415601 is a deficient number, since it is larger than the sum of its proper divisors (53417335603).

21420351415601 is an equidigital number, since it uses as much as digits as its factorization.

21420351415601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53417335602.

The product of its (nonzero) digits is 28800, while the sum is 35.

The spelling of 21420351415601 in words is "twenty-one trillion, four hundred twenty billion, three hundred fifty-one million, four hundred fifteen thousand, six hundred one".