1990388507 has 4 divisors (see below), whose sum is σ = 1999314240. Its totient is φ = 1981462776.

The previous prime is 1990388503. The next prime is 1990388549. The reversal of 1990388507 is 7058830991.

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

It is a cyclic number.

It is not a de Polignac number, because 1990388507 - 2² = 1990388503 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1990388503) 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, 4462532 + ... + 4462977.

It is an arithmetic number, because the mean of its divisors is an integer number (499828560).

Almost surely, 2^1990388507 is an apocalyptic number.

1990388507 is a deficient number, since it is larger than the sum of its proper divisors (8925733).

1990388507 is an equidigital number, since it uses as much as digits as its factorization.

1990388507 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8925732.

The product of its (nonzero) digits is 544320, while the sum is 50.

The square root of 1990388507 is about 44613.7703741793. The cubic root of 1990388507 is about 1257.8995210512.

The spelling of 1990388507 in words is "one billion, nine hundred ninety million, three hundred eighty-eight thousand, five hundred seven".