19961491979 has 32 divisors (see below), whose sum is σ = 24925555200. Its totient is φ = 15714984960.

The previous prime is 19961491951. The next prime is 19961491981. The reversal of 19961491979 is 97919416991.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19961491979 is a prime.

It is a super-2 number, since 2×19961491979² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (19961491079) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 244187 + ... + 315515.

It is an arithmetic number, because the mean of its divisors is an integer number (778923600).

Almost surely, 2^19961491979 is an apocalyptic number.

19961491979 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

19961491979 is a deficient number, since it is larger than the sum of its proper divisors (4964063221).

19961491979 is a wasteful number, since it uses less digits than its factorization.

19961491979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71475.

The product of its digits is 9920232, while the sum is 65.

The spelling of 19961491979 in words is "nineteen billion, nine hundred sixty-one million, four hundred ninety-one thousand, nine hundred seventy-nine".