19561501 has 4 divisors (see below), whose sum is σ = 19660000. Its totient is φ = 19463004.

The previous prime is 19561499. The next prime is 19561511. The reversal of 19561501 is 10516591.

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 19561501 - 2¹ = 19561499 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 19561501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19561511) 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 3 ways as a sum of consecutive naturals, for example, 48951 + ... + 49348.

It is an arithmetic number, because the mean of its divisors is an integer number (4915000).

Almost surely, 2^19561501 is an apocalyptic number.

It is an amenable number.

19561501 is a deficient number, since it is larger than the sum of its proper divisors (98499).

19561501 is an equidigital number, since it uses as much as digits as its factorization.

19561501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98498.

The product of its (nonzero) digits is 1350, while the sum is 28.

The square root of 19561501 is about 4422.8385681596. The cubic root of 19561501 is about 269.4433019810.

The spelling of 19561501 in words is "nineteen million, five hundred sixty-one thousand, five hundred one".