61778321 has 4 divisors (see below), whose sum is σ = 67394544. Its totient is φ = 56162100.

The previous prime is 61778317. The next prime is 61778341. The reversal of 61778321 is 12387716.

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 61778321 - 2² = 61778317 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61778341) 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, 2808095 + ... + 2808116.

It is an arithmetic number, because the mean of its divisors is an integer number (16848636).

Almost surely, 2^61778321 is an apocalyptic number.

It is an amenable number.

61778321 is a deficient number, since it is larger than the sum of its proper divisors (5616223).

61778321 is a wasteful number, since it uses less digits than its factorization.

61778321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5616222.

The product of its digits is 14112, while the sum is 35.

The square root of 61778321 is about 7859.9186382557. The cubic root of 61778321 is about 395.3168871943.

The spelling of 61778321 in words is "sixty-one million, seven hundred seventy-eight thousand, three hundred twenty-one".