18981619 has 8 divisors (see below), whose sum is σ = 19514880. Its totient is φ = 18452616.

The previous prime is 18981617. The next prime is 18981649. The reversal of 18981619 is 91618981.

It is a happy number.

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 18981619 - 2¹ = 18981617 is a prime.

It is a super-2 number, since 2×18981619² = 720603719722322, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (43).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18981617) 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, 9354 + ... + 11200.

It is an arithmetic number, because the mean of its divisors is an integer number (2439360).

Almost surely, 2^18981619 is an apocalyptic number.

18981619 is a deficient number, since it is larger than the sum of its proper divisors (533261).

18981619 is a wasteful number, since it uses less digits than its factorization.

18981619 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2129.

The product of its digits is 31104, while the sum is 43.

The square root of 18981619 is about 4356.7899880531. The cubic root of 18981619 is about 266.7540881777.

It can be divided in two parts, 18981 and 619, that added together give a square (19600 = 140²).

The spelling of 18981619 in words is "eighteen million, nine hundred eighty-one thousand, six hundred nineteen".