18717972 has 96 divisors (see below), whose sum is σ = 54829824. Its totient is φ = 4838400.

The previous prime is 18717971. The next prime is 18717977. The reversal of 18717972 is 27971781.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18717971) 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, 66472 + ... + 66752.

It is an arithmetic number, because the mean of its divisors is an integer number (571144).

Almost surely, 2^18717972 is an apocalyptic number.

18717972 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18717972, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27414912).

18717972 is an abundant number, since it is smaller than the sum of its proper divisors (36111852).

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

18717972 is a wasteful number, since it uses less digits than its factorization.

18717972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 369 (or 367 counting only the distinct ones).

The product of its digits is 49392, while the sum is 42.

The square root of 18717972 is about 4326.4271633763. The cubic root of 18717972 is about 265.5132901799.

The spelling of 18717972 in words is "eighteen million, seven hundred seventeen thousand, nine hundred seventy-two".