20948981 has 16 divisors (see below), whose sum is σ = 22934016. Its totient is φ = 19059456.

The previous prime is 20948969. The next prime is 20948987. The reversal of 20948981 is 18984902.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20948981 is a prime.

It is a super-2 number, since 2×20948981² = 877719609876722, 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 (20948987) 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, 125360 + ... + 125526.

It is an arithmetic number, because the mean of its divisors is an integer number (1433376).

Almost surely, 2^20948981 is an apocalyptic number.

It is an amenable number.

20948981 is a deficient number, since it is larger than the sum of its proper divisors (1985035).

20948981 is a wasteful number, since it uses less digits than its factorization.

20948981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 388.

The product of its (nonzero) digits is 41472, while the sum is 41.

The square root of 20948981 is about 4577.0056805733. The cubic root of 20948981 is about 275.6688117719.

The spelling of 20948981 in words is "twenty million, nine hundred forty-eight thousand, nine hundred eighty-one".