18870621 has 32 divisors (see below), whose sum is σ = 31635456. Its totient is φ = 9720000.

The previous prime is 18870611. The next prime is 18870623. The reversal of 18870621 is 12607881.

It is a happy number.

It is not a de Polignac number, because 18870621 - 2⁵ = 18870589 is a prime.

It is a super-2 number, since 2×18870621² = 712200673851282, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18870623) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 34611 + ... + 35151.

It is an arithmetic number, because the mean of its divisors is an integer number (988608).

Almost surely, 2^18870621 is an apocalyptic number.

18870621 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18870621 is a deficient number, since it is larger than the sum of its proper divisors (12764835).

18870621 is a wasteful number, since it uses less digits than its factorization.

18870621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 713.

The product of its (nonzero) digits is 5376, while the sum is 33.

The square root of 18870621 is about 4344.0328037435. The cubic root of 18870621 is about 266.2331092020.

It can be divided in two parts, 18870 and 621, that added together give a palindrome (19491).

The spelling of 18870621 in words is "eighteen million, eight hundred seventy thousand, six hundred twenty-one".