1985506157 has 2 divisors, whose sum is σ = 1985506158. Its totient is φ = 1985506156.

The previous prime is 1985506153. The next prime is 1985506219. The reversal of 1985506157 is 7516055891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1422345796 + 563160361 = 37714^2 + 23731^2 .

It is a cyclic number.

It is not a de Polignac number, because 1985506157 - 2² = 1985506153 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1985506153) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 992753078 + 992753079.

It is an arithmetic number, because the mean of its divisors is an integer number (992753079).

Almost surely, 2^1985506157 is an apocalyptic number.

It is an amenable number.

1985506157 is a deficient number, since it is larger than the sum of its proper divisors (1).

1985506157 is an equidigital number, since it uses as much as digits as its factorization.

1985506157 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 378000, while the sum is 47.

The square root of 1985506157 is about 44559.0188065222. The cubic root of 1985506157 is about 1256.8701517951.

The spelling of 1985506157 in words is "one billion, nine hundred eighty-five million, five hundred six thousand, one hundred fifty-seven".