1387501021 has 2 divisors, whose sum is σ = 1387501022. Its totient is φ = 1387501020.

The previous prime is 1387501009. The next prime is 1387501039. The reversal of 1387501021 is 1201057831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1034587225 + 352913796 = 32165^2 + 18786^2 .

It is a cyclic number.

It is not a de Polignac number, because 1387501021 - 2¹⁵ = 1387468253 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1387501721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 693750510 + 693750511.

It is an arithmetic number, because the mean of its divisors is an integer number (693750511).

Almost surely, 2^1387501021 is an apocalyptic number.

It is an amenable number.

1387501021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1387501021 is an equidigital number, since it uses as much as digits as its factorization.

1387501021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1680, while the sum is 28.

The square root of 1387501021 is about 37249.1747693825. The cubic root of 1387501021 is about 1115.3498258166.

Adding to 1387501021 its reverse (1201057831), we get a palindrome (2588558852).

The spelling of 1387501021 in words is "one billion, three hundred eighty-seven million, five hundred one thousand, twenty-one".