920257781 has 2 divisors, whose sum is σ = 920257782. Its totient is φ = 920257780.

The previous prime is 920257759. The next prime is 920257801. The reversal of 920257781 is 187752029.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 797158756 + 123099025 = 28234^2 + 11095^2 .

It is a cyclic number.

It is not a de Polignac number, because 920257781 - 2⁶ = 920257717 is a prime.

It is a super-2 number, since 2×920257781² = 1693748766982087922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (920257711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 460128890 + 460128891.

It is an arithmetic number, because the mean of its divisors is an integer number (460128891).

Almost surely, 2^920257781 is an apocalyptic number.

It is an amenable number.

920257781 is a deficient number, since it is larger than the sum of its proper divisors (1).

920257781 is an equidigital number, since it uses as much as digits as its factorization.

920257781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 70560, while the sum is 41.

The square root of 920257781 is about 30335.7508725266. The cubic root of 920257781 is about 972.6796564751.

The spelling of 920257781 in words is "nine hundred twenty million, two hundred fifty-seven thousand, seven hundred eighty-one".