19951720911 has 12 divisors (see below), whose sum is σ = 28821173992. Its totient is φ = 13300214256.

The previous prime is 19951720837. The next prime is 19951720913. The reversal of 19951720911 is 11902715991.

It is not a de Polignac number, because 19951720911 - 2¹¹ = 19951718863 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 (19951720913) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 73080 + ... + 212706.

Almost surely, 2^19951720911 is an apocalyptic number.

19951720911 is a deficient number, since it is larger than the sum of its proper divisors (8869453081).

19951720911 is a wasteful number, since it uses less digits than its factorization.

19951720911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155510 (or 155507 counting only the distinct ones).

The product of its (nonzero) digits is 51030, while the sum is 45.

The spelling of 19951720911 in words is "nineteen billion, nine hundred fifty-one million, seven hundred twenty thousand, nine hundred eleven".