129921990806 has 4 divisors (see below), whose sum is σ = 194882986212. Its totient is φ = 64960995402.

The previous prime is 129921990749. The next prime is 129921990811. The reversal of 129921990806 is 608099129921.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 608099129921 = 131 ⋅4641978091.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32480497700 + ... + 32480497703.

It is an arithmetic number, because the mean of its divisors is an integer number (48720746553).

Almost surely, 2^129921990806 is an apocalyptic number.

129921990806 is a deficient number, since it is larger than the sum of its proper divisors (64960995406).

129921990806 is an equidigital number, since it uses as much as digits as its factorization.

129921990806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64960995405.

The product of its (nonzero) digits is 1259712, while the sum is 56.

The spelling of 129921990806 in words is "one hundred twenty-nine billion, nine hundred twenty-one million, nine hundred ninety thousand, eight hundred six".