61701991 has 16 divisors (see below), whose sum is σ = 67765824. Its totient is φ = 55839744.

The previous prime is 61701979. The next prime is 61702001. The reversal of 61701991 is 19910716.

It is a cyclic number.

It is not a de Polignac number, because 61701991 - 2¹⁷ = 61570919 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 (61701901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 210441 + ... + 210733.

It is an arithmetic number, because the mean of its divisors is an integer number (4235364).

Almost surely, 2^61701991 is an apocalyptic number.

61701991 is a deficient number, since it is larger than the sum of its proper divisors (6063833).

61701991 is a wasteful number, since it uses less digits than its factorization.

61701991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 570.

The product of its (nonzero) digits is 3402, while the sum is 34.

The square root of 61701991 is about 7855.0614892565. The cubic root of 61701991 is about 395.1540092710.

The spelling of 61701991 in words is "sixty-one million, seven hundred one thousand, nine hundred ninety-one".