20100981 has 4 divisors (see below), whose sum is σ = 26801312. Its totient is φ = 13400652.

The previous prime is 20100943. The next prime is 20100991. The reversal of 20100981 is 18900102.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20100981 - 2⁷ = 20100853 is a prime.

It is a super-2 number, since 2×20100981² = 808098874324722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20100911) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3350161 + ... + 3350166.

It is an arithmetic number, because the mean of its divisors is an integer number (6700328).

Almost surely, 2^20100981 is an apocalyptic number.

It is an amenable number.

20100981 is a deficient number, since it is larger than the sum of its proper divisors (6700331).

20100981 is an equidigital number, since it uses as much as digits as its factorization.

20100981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6700330.

The product of its (nonzero) digits is 144, while the sum is 21.

The square root of 20100981 is about 4483.4117589175. The cubic root of 20100981 is about 271.8978359468.

The spelling of 20100981 in words is "twenty million, one hundred thousand, nine hundred eighty-one".