1387067721 has 16 divisors (see below), whose sum is σ = 1992856320. Its totient is φ = 853079040.

The previous prime is 1387067707. The next prime is 1387067743. The reversal of 1387067721 is 1277607831.

It is a happy number.

It is not a de Polignac number, because 1387067721 - 2⁶ = 1387067657 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1387067771) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 63465 + ... + 82473.

It is an arithmetic number, because the mean of its divisors is an integer number (124553520).

Almost surely, 2^1387067721 is an apocalyptic number.

It is an amenable number.

1387067721 is a deficient number, since it is larger than the sum of its proper divisors (605788599).

1387067721 is a wasteful number, since it uses less digits than its factorization.

1387067721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20896.

The product of its (nonzero) digits is 98784, while the sum is 42.

The square root of 1387067721 is about 37243.3580789917. The cubic root of 1387067721 is about 1115.2337102514.

The spelling of 1387067721 in words is "one billion, three hundred eighty-seven million, sixty-seven thousand, seven hundred twenty-one".