615421 has 4 divisors (see below), whose sum is σ = 632092. Its totient is φ = 598752.

The previous prime is 615413. The next prime is 615427. The reversal of 615421 is 124516.

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 324900 + 290521 = 570^2 + 539^2 .

It is a cyclic number.

It is not a de Polignac number, because 615421 - 2³ = 615413 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (615427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8280 + ... + 8353.

It is an arithmetic number, because the mean of its divisors is an integer number (158023).

2⁶¹⁵⁴²¹ is an apocalyptic number.

It is an amenable number.

615421 is a deficient number, since it is larger than the sum of its proper divisors (16671).

615421 is a wasteful number, since it uses less digits than its factorization.

615421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16670.

The product of its digits is 240, while the sum is 19.

The square root of 615421 is about 784.4877309429. The cubic root of 615421 is about 85.0597503764.

Adding to 615421 its reverse (124516), we get a palindrome (739937).

The spelling of 615421 in words is "six hundred fifteen thousand, four hundred twenty-one".