385406297721 has 21 divisors (see below), whose sum is σ = 577870239999. Its totient is φ = 256926357216.

The previous prime is 385406297711. The next prime is 385406297737. The reversal of 385406297721 is 127792604583.

It is a happy number.

The square root of 385406297721 is 620811.

It is a perfect power (a square), and thus also a powerful number.

385406297721 is a `hidden beast` number, since 3 + 8 + 5 + 4 + 0 + 629 + 7 + 7 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 315849620025 + 69556677696 = 562005^2 + 263736^2 .

It is not a de Polignac number, because 385406297721 - 2⁹ = 385406297209 is a prime.

It is not an unprimeable number, because it can be changed into a prime (385406297701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 20 ways as a sum of consecutive naturals, for example, 16750401 + ... + 16773393.

It is a 1-persistent number, because it is pandigital, but 2⋅385406297721 = 770812595442 is not.

Almost surely, 2^385406297721 is an apocalyptic number.

385406297721 is the 620811-st square number.

385406297721 is the 310406-th centered octagonal number.

It is an amenable number.

385406297721 is a deficient number, since it is larger than the sum of its proper divisors (192463942278).

385406297721 is an frugal number, since it uses more digits than its factorization.

385406297721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46004 (or 22996 counting only the distinct ones).

The product of its (nonzero) digits is 5080320, while the sum is 54.

The spelling of 385406297721 in words is "three hundred eighty-five billion, four hundred six million, two hundred ninety-seven thousand, seven hundred twenty-one".