1386610921 has 4 divisors (see below), whose sum is σ = 1400339844. Its totient is φ = 1372882000.

The previous prime is 1386610903. The next prime is 1386610961. The reversal of 1386610921 is 1290166831.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1153621225 + 232989696 = 33965^2 + 15264^2 .

It is a cyclic number.

It is not a de Polignac number, because 1386610921 - 2⁵ = 1386610889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1386610961) 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, 6864310 + ... + 6864511.

It is an arithmetic number, because the mean of its divisors is an integer number (350084961).

Almost surely, 2^1386610921 is an apocalyptic number.

It is an amenable number.

1386610921 is a deficient number, since it is larger than the sum of its proper divisors (13728923).

1386610921 is a wasteful number, since it uses less digits than its factorization.

1386610921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13728922.

The product of its (nonzero) digits is 15552, while the sum is 37.

The square root of 1386610921 is about 37237.2249368827. The cubic root of 1386610921 is about 1115.1112709776. Note that the first 3 decimals are identical.

The spelling of 1386610921 in words is "one billion, three hundred eighty-six million, six hundred ten thousand, nine hundred twenty-one".