388349921 has 8 divisors (see below), whose sum is σ = 418953384. Its totient is φ = 358608640.

The previous prime is 388349903. The next prime is 388349947. The reversal of 388349921 is 129943883.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 120209296 + 268140625 = 10964^2 + 16375^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 388349921 - 2²⁶ = 321241057 is a prime.

It is a super-2 number, since 2×388349921² = 301631322281412482, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (388340921) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 214610 + ... + 216411.

It is an arithmetic number, because the mean of its divisors is an integer number (52369173).

Almost surely, 2^388349921 is an apocalyptic number.

It is an amenable number.

388349921 is a deficient number, since it is larger than the sum of its proper divisors (30603463).

388349921 is a wasteful number, since it uses less digits than its factorization.

388349921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 431091.

The product of its digits is 373248, while the sum is 47.

The square root of 388349921 is about 19706.5958754931. The cubic root of 388349921 is about 729.5824978659.

The spelling of 388349921 in words is "three hundred eighty-eight million, three hundred forty-nine thousand, nine hundred twenty-one".