61556399 has 2 divisors, whose sum is σ = 61556400. Its totient is φ = 61556398.

The previous prime is 61556387. The next prime is 61556431. The reversal of 61556399 is 99365516.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 61556399 - 2¹² = 61552303 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61556329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30778199 + 30778200.

It is an arithmetic number, because the mean of its divisors is an integer number (30778200).

Almost surely, 2^61556399 is an apocalyptic number.

61556399 is a deficient number, since it is larger than the sum of its proper divisors (1).

61556399 is an equidigital number, since it uses as much as digits as its factorization.

61556399 is an evil number, because the sum of its binary digits is even.

The product of its digits is 218700, while the sum is 44.

The square root of 61556399 is about 7845.7886155568. The cubic root of 61556399 is about 394.8429627323.

The spelling of 61556399 in words is "sixty-one million, five hundred fifty-six thousand, three hundred ninety-nine".