1388781620 has 12 divisors (see below), whose sum is σ = 2916441444. Its totient is φ = 555512640.

The previous prime is 1388781619. The next prime is 1388781661. The reversal of 1388781620 is 261878831.

It can be written as a sum of positive squares in 2 ways, for example, as 1006031524 + 382750096 = 31718^2 + 19564^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34719521 + ... + 34719560.

It is an arithmetic number, because the mean of its divisors is an integer number (243036787).

Almost surely, 2^1388781620 is an apocalyptic number.

1388781620 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1388781620 is an abundant number, since it is smaller than the sum of its proper divisors (1527659824).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1388781620 is a wasteful number, since it uses less digits than its factorization.

1388781620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69439090 (or 69439088 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 44.

The square root of 1388781620 is about 37266.3604340429. The cubic root of 1388781620 is about 1115.6928589993.

The spelling of 1388781620 in words is "one billion, three hundred eighty-eight million, seven hundred eighty-one thousand, six hundred twenty".