18728461 has 8 divisors (see below), whose sum is σ = 19491480. Its totient is φ = 17973312.

The previous prime is 18728459. The next prime is 18728467. The reversal of 18728461 is 16482781.

It can be written as a sum of positive squares in 4 ways, for example, as 7209225 + 11519236 = 2685^2 + 3394^2 .

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 18728461 - 2¹ = 18728459 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18728461.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18728467) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3151 + ... + 6883.

It is an arithmetic number, because the mean of its divisors is an integer number (2436435).

Almost surely, 2^18728461 is an apocalyptic number.

It is an amenable number.

18728461 is a deficient number, since it is larger than the sum of its proper divisors (763019).

18728461 is a wasteful number, since it uses less digits than its factorization.

18728461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3935.

The product of its digits is 21504, while the sum is 37.

The square root of 18728461 is about 4327.6391947573. The cubic root of 18728461 is about 265.5628761938.

The spelling of 18728461 in words is "eighteen million, seven hundred twenty-eight thousand, four hundred sixty-one".