20191000 has 64 divisors (see below), whose sum is σ = 48166560. Its totient is φ = 7920000.

The previous prime is 20190943. The next prime is 20191009. The reversal of 20191000 is 19102.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20191009) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 60835 + ... + 61165.

Almost surely, 2^20191000 is an apocalyptic number.

20191000 is a gapful number since it is divisible by the number (20) 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 20191000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24083280).

20191000 is an abundant number, since it is smaller than the sum of its proper divisors (27975560).

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

20191000 is a wasteful number, since it uses less digits than its factorization.

20191000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 413 (or 399 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 13.

The square root of 20191000 is about 4493.4396624412. The cubic root of 20191000 is about 272.3031150838.

The spelling of 20191000 in words is "twenty million, one hundred ninety-one thousand".