42778321 has 4 divisors (see below), whose sum is σ = 44638272. Its totient is φ = 40918372.

The previous prime is 42778303. The next prime is 42778349. The reversal of 42778321 is 12387724.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 42778321 - 2⁵ = 42778289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42778381) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 929941 + ... + 929986.

It is an arithmetic number, because the mean of its divisors is an integer number (11159568).

Almost surely, 2^42778321 is an apocalyptic number.

It is an amenable number.

42778321 is a deficient number, since it is larger than the sum of its proper divisors (1859951).

42778321 is a wasteful number, since it uses less digits than its factorization.

42778321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1859950.

The product of its digits is 18816, while the sum is 34.

The square root of 42778321 is about 6540.5138177363. The cubic root of 42778321 is about 349.7367299090.

The spelling of 42778321 in words is "forty-two million, seven hundred seventy-eight thousand, three hundred twenty-one".