387990521 has 2 divisors, whose sum is σ = 387990522. Its totient is φ = 387990520.

The previous prime is 387990511. The next prime is 387990539. The reversal of 387990521 is 125099783.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 385572496 + 2418025 = 19636^2 + 1555^2 .

It is a cyclic number.

It is not a de Polignac number, because 387990521 - 2⁶ = 387990457 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (387990511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 193995260 + 193995261.

It is an arithmetic number, because the mean of its divisors is an integer number (193995261).

Almost surely, 2^387990521 is an apocalyptic number.

It is an amenable number.

387990521 is a deficient number, since it is larger than the sum of its proper divisors (1).

387990521 is an equidigital number, since it uses as much as digits as its factorization.

387990521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 136080, while the sum is 44.

The square root of 387990521 is about 19697.4749904651. The cubic root of 387990521 is about 729.3573633797.

The spelling of 387990521 in words is "three hundred eighty-seven million, nine hundred ninety thousand, five hundred twenty-one".