20506457851 has 8 divisors (see below), whose sum is σ = 22372761600. Its totient is φ = 18640500840.

The previous prime is 20506457837. The next prime is 20506457857. The reversal of 20506457851 is 15875460502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20506457851 - 2¹³ = 20506449659 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20506457798 and 20506457807.

It is not an unprimeable number, because it can be changed into a prime (20506457857) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 45790 + ... + 207628.

It is an arithmetic number, because the mean of its divisors is an integer number (2796595200).

Almost surely, 2^20506457851 is an apocalyptic number.

20506457851 is a deficient number, since it is larger than the sum of its proper divisors (1866303749).

20506457851 is a wasteful number, since it uses less digits than its factorization.

20506457851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173369.

The product of its (nonzero) digits is 336000, while the sum is 43.

The spelling of 20506457851 in words is "twenty billion, five hundred six million, four hundred fifty-seven thousand, eight hundred fifty-one".