646021151 has 4 divisors (see below), whose sum is σ = 646144704. Its totient is φ = 645897600.

The previous prime is 646021127. The next prime is 646021153. The reversal of 646021151 is 151120646.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 151120646 = 2 ⋅75560323.

It is a cyclic number.

It is not a de Polignac number, because 646021151 - 2²² = 641826847 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 646021151.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646021153) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53570 + ... + 64511.

It is an arithmetic number, because the mean of its divisors is an integer number (161536176).

Almost surely, 2^646021151 is an apocalyptic number.

646021151 is a deficient number, since it is larger than the sum of its proper divisors (123553).

646021151 is a wasteful number, since it uses less digits than its factorization.

646021151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123552.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 646021151 is about 25416.9461383542. The cubic root of 646021151 is about 864.4679816243.

Adding to 646021151 its reverse (151120646), we get a palindrome (797141797).

The spelling of 646021151 in words is "six hundred forty-six million, twenty-one thousand, one hundred fifty-one".