18971961 has 8 divisors (see below), whose sum is σ = 25317120. Its totient is φ = 12637392.

The previous prime is 18971959. The next prime is 18971993. The reversal of 18971961 is 16917981.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18971961 - 2¹ = 18971959 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18971461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3735 + ... + 7203.

It is an arithmetic number, because the mean of its divisors is an integer number (3164640).

Almost surely, 2^18971961 is an apocalyptic number.

It is an amenable number.

18971961 is a deficient number, since it is larger than the sum of its proper divisors (6345159).

18971961 is a wasteful number, since it uses less digits than its factorization.

18971961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5295.

The product of its digits is 27216, while the sum is 42.

The square root of 18971961 is about 4355.6814621825. The cubic root of 18971961 is about 266.7088382958.

The spelling of 18971961 in words is "eighteen million, nine hundred seventy-one thousand, nine hundred sixty-one".