920918981 has 2 divisors, whose sum is σ = 920918982. Its totient is φ = 920918980.

The previous prime is 920918969. The next prime is 920919001. The reversal of 920918981 is 189819029.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 914518081 + 6400900 = 30241^2 + 2530^2 .

It is an emirp because it is prime and its reverse (189819029) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-920918981 is a prime.

It is a super-2 number, since 2×920918981² = 1696183539132156722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (920918941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 460459490 + 460459491.

It is an arithmetic number, because the mean of its divisors is an integer number (460459491).

Almost surely, 2^920918981 is an apocalyptic number.

It is an amenable number.

920918981 is a deficient number, since it is larger than the sum of its proper divisors (1).

920918981 is an equidigital number, since it uses as much as digits as its factorization.

920918981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 93312, while the sum is 47.

The square root of 920918981 is about 30346.6469482215. The cubic root of 920918981 is about 972.9125556453.

The spelling of 920918981 in words is "nine hundred twenty million, nine hundred eighteen thousand, nine hundred eighty-one".