712256121821 has 4 divisors (see below), whose sum is σ = 713503506144. Its totient is φ = 711008737500.

The previous prime is 712256121751. The next prime is 712256121839. The reversal of 712256121821 is 128121652217.

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: 128121652217 = 13 ⋅9855511709.

It is a cyclic number.

It is not a de Polignac number, because 712256121821 - 2¹⁴ = 712256105437 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 (712256121121) 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, 623691305 + ... + 623692446.

It is an arithmetic number, because the mean of its divisors is an integer number (178375876536).

Almost surely, 2^712256121821 is an apocalyptic number.

It is an amenable number.

712256121821 is a deficient number, since it is larger than the sum of its proper divisors (1247384323).

712256121821 is a wasteful number, since it uses less digits than its factorization.

712256121821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1247384322.

The product of its digits is 26880, while the sum is 38.

The spelling of 712256121821 in words is "seven hundred twelve billion, two hundred fifty-six million, one hundred twenty-one thousand, eight hundred twenty-one".