61778399 has 4 divisors (see below), whose sum is σ = 61803840. Its totient is φ = 61752960.

The previous prime is 61778383. The next prime is 61778407. The reversal of 61778399 is 99387716.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 61778399 - 2⁴ = 61778383 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 (61778309) 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, 8642 + ... + 14079.

It is an arithmetic number, because the mean of its divisors is an integer number (15450960).

Almost surely, 2^61778399 is an apocalyptic number.

61778399 is a deficient number, since it is larger than the sum of its proper divisors (25441).

61778399 is a wasteful number, since it uses less digits than its factorization.

61778399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25440.

The product of its digits is 571536, while the sum is 50.

The square root of 61778399 is about 7859.9236001376. The cubic root of 61778399 is about 395.3170535671.

The spelling of 61778399 in words is "sixty-one million, seven hundred seventy-eight thousand, three hundred ninety-nine".