61809563 has 2 divisors, whose sum is σ = 61809564. Its totient is φ = 61809562.

The previous prime is 61809493. The next prime is 61809581. The reversal of 61809563 is 36590816.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 61809563 - 2¹⁸ = 61547419 is a prime.

It is not a weakly prime, because it can be changed into another prime (61809593) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30904781 + 30904782.

It is an arithmetic number, because the mean of its divisors is an integer number (30904782).

Almost surely, 2^61809563 is an apocalyptic number.

61809563 is a deficient number, since it is larger than the sum of its proper divisors (1).

61809563 is an equidigital number, since it uses as much as digits as its factorization.

61809563 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 38880, while the sum is 38.

The square root of 61809563 is about 7861.9058122061. The cubic root of 61809563 is about 395.3835147137.

The spelling of 61809563 in words is "sixty-one million, eight hundred nine thousand, five hundred sixty-three".