19974447991 has 16 divisors (see below), whose sum is σ = 20222979840. Its totient is φ = 19727971200.

The previous prime is 19974447973. The next prime is 19974448099.

19974447991 = T₁₅₃₈₃ + T₁₅₃₈₄ + ... + T₁₅₅₄₉.

19974447991 is nontrivially palindromic in base 10.

It is a cyclic number.

It is not a de Polignac number, because 19974447991 - 2¹⁷ = 19974316919 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 (19974447901) 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 15 ways as a sum of consecutive naturals, for example, 25380100 + ... + 25380886.

It is an arithmetic number, because the mean of its divisors is an integer number (1263936240).

Almost surely, 2^19974447991 is an apocalyptic number.

19974447991 is a deficient number, since it is larger than the sum of its proper divisors (248531849).

19974447991 is a wasteful number, since it uses less digits than its factorization.

19974447991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1734.

The product of its digits is 20575296, while the sum is 64.

The spelling of 19974447991 in words is "nineteen billion, nine hundred seventy-four million, four hundred forty-seven thousand, nine hundred ninety-one".