20143981 has 8 divisors (see below), whose sum is σ = 23665824. Its totient is φ = 16903920.

The previous prime is 20143979. The next prime is 20143999. The reversal of 20143981 is 18934102.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20143981 - 2¹ = 20143979 is a prime.

It is a super-2 number, since 2×20143981² = 811559941056722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20143901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 70291 + ... + 70576.

It is an arithmetic number, because the mean of its divisors is an integer number (2958228).

Almost surely, 2^20143981 is an apocalyptic number.

It is an amenable number.

20143981 is a deficient number, since it is larger than the sum of its proper divisors (3521843).

20143981 is a wasteful number, since it uses less digits than its factorization.

20143981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140891.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 20143981 is about 4488.2046521967. The cubic root of 20143981 is about 272.0915790606.

It can be divided in two parts, 2014 and 3981, that added together give a palindrome (5995).

The spelling of 20143981 in words is "twenty million, one hundred forty-three thousand, nine hundred eighty-one".