19998972 has 72 divisors (see below), whose sum is σ = 58767072. Its totient is φ = 5616000.

The previous prime is 19998949. The next prime is 19998977. The reversal of 19998972 is 27989991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19998977) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14722 + ... + 16022.

Almost surely, 2^19998972 is an apocalyptic number.

19998972 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 19998972, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29383536).

19998972 is an abundant number, since it is smaller than the sum of its proper divisors (38768100).

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

19998972 is a wasteful number, since it uses less digits than its factorization.

19998972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1379 (or 1374 counting only the distinct ones).

The product of its digits is 734832, while the sum is 54.

The square root of 19998972 is about 4472.0210196286. The cubic root of 19998972 is about 271.4371108776.

It can be divided in two parts, 19 and 998972, that added together give a triangular number (998991 = T₁₄₁₃).

The spelling of 19998972 in words is "nineteen million, nine hundred ninety-eight thousand, nine hundred seventy-two".