18961440 has 48 divisors (see below), whose sum is σ = 59730048. Its totient is φ = 5056256.

The previous prime is 18961417. The next prime is 18961441. The reversal of 18961440 is 4416981.

It is a tau number, because it is divible by the number of its divisors (48).

It is not an unprimeable number, because it can be changed into a prime (18961441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19272 + ... + 20231.

It is an arithmetic number, because the mean of its divisors is an integer number (1244376).

Almost surely, 2^18961440 is an apocalyptic number.

18961440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18961440 is an abundant number, since it is smaller than the sum of its proper divisors (40768608).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18961440 is a wasteful number, since it uses less digits than its factorization.

18961440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39521 (or 39513 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 33.

The square root of 18961440 is about 4354.4735617523. The cubic root of 18961440 is about 266.6595275867.

The spelling of 18961440 in words is "eighteen million, nine hundred sixty-one thousand, four hundred forty".