21406735756541 has 4 divisors (see below), whose sum is σ = 21407030440284. Its totient is φ = 21406441072800.

The previous prime is 21406735756531. The next prime is 21406735756603. The reversal of 21406735756541 is 14565753760412.

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 887910444100 + 20518825312441 = 942290^2 + 4529771^2 .

It is a cyclic number.

It is not a de Polignac number, because 21406735756541 - 2²⁶ = 21406668647677 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21406735756531) 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, 147232880 + ... + 147378201.

It is an arithmetic number, because the mean of its divisors is an integer number (5351757610071).

Almost surely, 2^{21406735756541} is an apocalyptic number.

It is an amenable number.

21406735756541 is a deficient number, since it is larger than the sum of its proper divisors (294683743).

21406735756541 is an equidigital number, since it uses as much as digits as its factorization.

21406735756541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 294683742.

The product of its (nonzero) digits is 21168000, while the sum is 56.

The spelling of 21406735756541 in words is "twenty-one trillion, four hundred six billion, seven hundred thirty-five million, seven hundred fifty-six thousand, five hundred forty-one".