1397639989 has 4 divisors (see below), whose sum is σ = 1479854124. Its totient is φ = 1315425856.

The previous prime is 1397639941. The next prime is 1397639993. The reversal of 1397639989 is 9899367931.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1086823089 + 310816900 = 32967^2 + 17630^2 .

It is a cyclic number.

It is not a de Polignac number, because 1397639989 - 2¹³ = 1397631797 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1397639989.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1397639489) 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, 41107042 + ... + 41107075.

It is an arithmetic number, because the mean of its divisors is an integer number (369963531).

Almost surely, 2^1397639989 is an apocalyptic number.

It is an amenable number.

1397639989 is a deficient number, since it is larger than the sum of its proper divisors (82214135).

1397639989 is an equidigital number, since it uses as much as digits as its factorization.

1397639989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82214134.

The product of its digits is 19840464, while the sum is 64.

The square root of 1397639989 is about 37385.0235923424. The cubic root of 1397639989 is about 1118.0599889619.

It can be divided in two parts, 1397639 and 989, that added together give a triangular number (1398628 = T₁₆₇₂).

The spelling of 1397639989 in words is "one billion, three hundred ninety-seven million, six hundred thirty-nine thousand, nine hundred eighty-nine".