19478661 has 4 divisors (see below), whose sum is σ = 25971552. Its totient is φ = 12985772.

The previous prime is 19478659. The next prime is 19478671. The reversal of 19478661 is 16687491.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 19478661 - 2¹ = 19478659 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19478611) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3246441 + ... + 3246446.

It is an arithmetic number, because the mean of its divisors is an integer number (6492888).

Almost surely, 2^19478661 is an apocalyptic number.

It is an amenable number.

19478661 is a deficient number, since it is larger than the sum of its proper divisors (6492891).

19478661 is an equidigital number, since it uses as much as digits as its factorization.

19478661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6492890.

The product of its digits is 72576, while the sum is 42.

The square root of 19478661 is about 4413.4636058316. The cubic root of 19478661 is about 269.0624132528.

The spelling of 19478661 in words is "nineteen million, four hundred seventy-eight thousand, six hundred sixty-one".