905851561 has 2 divisors, whose sum is σ = 905851562. Its totient is φ = 905851560.

The previous prime is 905851559. The next prime is 905851577. The reversal of 905851561 is 165158509.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 900000000 + 5851561 = 30000^2 + 2419^2 .

It is a cyclic number.

It is not a de Polignac number, because 905851561 - 2¹ = 905851559 is a prime.

It is a super-2 number, since 2×905851561² = 1641134101132273442, which contains 22 as substring.

Together with 905851559, it forms a pair of twin primes.

It is a weakly prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 452925780 + 452925781.

It is an arithmetic number, because the mean of its divisors is an integer number (452925781).

Almost surely, 2^905851561 is an apocalyptic number.

It is an amenable number.

905851561 is a deficient number, since it is larger than the sum of its proper divisors (1).

905851561 is an equidigital number, since it uses as much as digits as its factorization.

905851561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54000, while the sum is 40.

The square root of 905851561 is about 30097.3680078508. The cubic root of 905851561 is about 967.5773179223.

The spelling of 905851561 in words is "nine hundred five million, eight hundred fifty-one thousand, five hundred sixty-one".