19912661 has 8 divisors (see below), whose sum is σ = 21352320. Its totient is φ = 18502848.

The previous prime is 19912649. The next prime is 19912663. The reversal of 19912661 is 16621991.

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

It is a cyclic number.

It is not a de Polignac number, because 19912661 - 2⁶ = 19912597 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 (19912663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6071 + ... + 8756.

It is an arithmetic number, because the mean of its divisors is an integer number (2669040).

Almost surely, 2^19912661 is an apocalyptic number.

It is an amenable number.

19912661 is a deficient number, since it is larger than the sum of its proper divisors (1439659).

19912661 is a wasteful number, since it uses less digits than its factorization.

19912661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14923.

The product of its digits is 5832, while the sum is 35.

The square root of 19912661 is about 4462.3604740092. The cubic root of 19912661 is about 271.0460608971.

The spelling of 19912661 in words is "nineteen million, nine hundred twelve thousand, six hundred sixty-one".