61981549 has 16 divisors (see below), whose sum is σ = 73237248. Its totient is φ = 51345792.

The previous prime is 61981537. The next prime is 61981561. The reversal of 61981549 is 94518916.

It is an interprime number because it is at equal distance from previous prime (61981537) and next prime (61981561).

It is a cyclic number.

It is not a de Polignac number, because 61981549 - 2¹³ = 61973357 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61981349) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42537 + ... + 43969.

It is an arithmetic number, because the mean of its divisors is an integer number (4577328).

Almost surely, 2^61981549 is an apocalyptic number.

It is an amenable number.

61981549 is a deficient number, since it is larger than the sum of its proper divisors (11255699).

61981549 is a wasteful number, since it uses less digits than its factorization.

61981549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1644.

The product of its digits is 77760, while the sum is 43.

The square root of 61981549 is about 7872.8361471582. The cubic root of 61981549 is about 395.7498952135.

The spelling of 61981549 in words is "sixty-one million, nine hundred eighty-one thousand, five hundred forty-nine".