61771561 has 4 divisors (see below), whose sum is σ = 63764224. Its totient is φ = 59778900.

The previous prime is 61771559. The next prime is 61771573. The reversal of 61771561 is 16517716.

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 61771561 - 2¹ = 61771559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61771531) 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, 996285 + ... + 996346.

It is an arithmetic number, because the mean of its divisors is an integer number (15941056).

Almost surely, 2^61771561 is an apocalyptic number.

It is an amenable number.

61771561 is a deficient number, since it is larger than the sum of its proper divisors (1992663).

61771561 is a wasteful number, since it uses less digits than its factorization.

61771561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1992662.

The product of its digits is 8820, while the sum is 34.

The square root of 61771561 is about 7859.4885965946. The cubic root of 61771561 is about 395.3024676827.

The spelling of 61771561 in words is "sixty-one million, seven hundred seventy-one thousand, five hundred sixty-one".