561378021 has 8 divisors (see below), whose sum is σ = 749942784. Its totient is φ = 373532640.

The previous prime is 561378019. The next prime is 561378071. The reversal of 561378021 is 120873165.

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

It is not a de Polignac number, because 561378021 - 2¹ = 561378019 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561378001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 178021 + ... + 181146.

It is an arithmetic number, because the mean of its divisors is an integer number (93742848).

Almost surely, 2^561378021 is an apocalyptic number.

It is an amenable number.

561378021 is a deficient number, since it is larger than the sum of its proper divisors (188564763).

561378021 is a wasteful number, since it uses less digits than its factorization.

561378021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 359691.

The product of its (nonzero) digits is 10080, while the sum is 33.

The square root of 561378021 is about 23693.4172503672. The cubic root of 561378021 is about 824.9326034934.

The spelling of 561378021 in words is "five hundred sixty-one million, three hundred seventy-eight thousand, twenty-one".