1989257077 has 4 divisors (see below), whose sum is σ = 1997182656. Its totient is φ = 1981331500.

The previous prime is 1989257071. The next prime is 1989257087. The reversal of 1989257077 is 7707529891.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1989257077 - 2¹⁵ = 1989224309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1989257071) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3962413 + ... + 3962914.

It is an arithmetic number, because the mean of its divisors is an integer number (499295664).

Almost surely, 2^1989257077 is an apocalyptic number.

It is an amenable number.

1989257077 is a deficient number, since it is larger than the sum of its proper divisors (7925579).

1989257077 is an equidigital number, since it uses as much as digits as its factorization.

1989257077 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7925578.

The product of its (nonzero) digits is 2222640, while the sum is 55.

The square root of 1989257077 is about 44601.0882938970. The cubic root of 1989257077 is about 1257.6611262167.

The spelling of 1989257077 in words is "one billion, nine hundred eighty-nine million, two hundred fifty-seven thousand, seventy-seven".