18977431 has 4 divisors (see below), whose sum is σ = 20702664. Its totient is φ = 17252200.

The previous prime is 18977429. The next prime is 18977437. The reversal of 18977431 is 13477981.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 18977431 - 2¹ = 18977429 is a prime.

It is a super-2 number, since 2×18977431² = 720285774719522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18977437) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 862600 + ... + 862621.

It is an arithmetic number, because the mean of its divisors is an integer number (5175666).

Almost surely, 2^18977431 is an apocalyptic number.

18977431 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

18977431 is a deficient number, since it is larger than the sum of its proper divisors (1725233).

18977431 is a wasteful number, since it uses less digits than its factorization.

18977431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1725232.

The product of its digits is 42336, while the sum is 40.

The square root of 18977431 is about 4356.3093324510. The cubic root of 18977431 is about 266.7344683498.

The spelling of 18977431 in words is "eighteen million, nine hundred seventy-seven thousand, four hundred thirty-one".