1387664020 has 24 divisors (see below), whose sum is σ = 2969079624. Its totient is φ = 544592256.

The previous prime is 1387664009. The next prime is 1387664023. The reversal of 1387664020 is 204667831.

It can be written as a sum of positive squares in 4 ways, for example, as 440748036 + 946915984 = 20994^2 + 30772^2 .

It is a super-2 number, since 2×1387664020² = 3851222864805120800, which contains 22 as substring.

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1387664023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 653499 + ... + 655618.

It is an arithmetic number, because the mean of its divisors is an integer number (123711651).

Almost surely, 2^1387664020 is an apocalyptic number.

1387664020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1387664020 is an abundant number, since it is smaller than the sum of its proper divisors (1581415604).

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

1387664020 is a wasteful number, since it uses less digits than its factorization.

1387664020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1309179 (or 1309177 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 37.

The square root of 1387664020 is about 37251.3626596397. The cubic root of 1387664020 is about 1115.3934999676.

The spelling of 1387664020 in words is "one billion, three hundred eighty-seven million, six hundred sixty-four thousand, twenty".