10856139721 has 4 divisors (see below), whose sum is σ = 12407016832. Its totient is φ = 9305262612.

The previous prime is 10856139719. The next prime is 10856139731. The reversal of 10856139721 is 12793165801.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12793165801 = 13 ⋅984089677.

It is a cyclic number.

It is not a de Polignac number, because 10856139721 - 2¹ = 10856139719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (10856139731) 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, 775438545 + ... + 775438558.

It is an arithmetic number, because the mean of its divisors is an integer number (3101754208).

Almost surely, 2^10856139721 is an apocalyptic number.

It is an amenable number.

10856139721 is a deficient number, since it is larger than the sum of its proper divisors (1550877111).

10856139721 is an equidigital number, since it uses as much as digits as its factorization.

10856139721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1550877110.

The product of its (nonzero) digits is 90720, while the sum is 43.

The spelling of 10856139721 in words is "ten billion, eight hundred fifty-six million, one hundred thirty-nine thousand, seven hundred twenty-one".