21106753747 has 4 divisors (see below), whose sum is σ = 21156888976. Its totient is φ = 21056618520.

The previous prime is 21106753741. The next prime is 21106753757. The reversal of 21106753747 is 74735760112.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21106753747 - 2³ = 21106753739 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21106753741) 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, 25066983 + ... + 25067824.

It is an arithmetic number, because the mean of its divisors is an integer number (5289222244).

Almost surely, 2^21106753747 is an apocalyptic number.

21106753747 is a deficient number, since it is larger than the sum of its proper divisors (50135229).

21106753747 is an equidigital number, since it uses as much as digits as its factorization.

21106753747 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50135228.

The product of its (nonzero) digits is 246960, while the sum is 43.

The spelling of 21106753747 in words is "twenty-one billion, one hundred six million, seven hundred fifty-three thousand, seven hundred forty-seven".