61491584 has 128 divisors (see below), whose sum is σ = 162155520. Its totient is φ = 22487040.

The previous prime is 61491583. The next prime is 61491611. The reversal of 61491584 is 48519416.

61491584 = 357² + 358² + ... + 612².

It is a tau number, because it is divible by the number of its divisors (128).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61491583) 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, 167369 + ... + 167735.

It is an arithmetic number, because the mean of its divisors is an integer number (1266840).

Almost surely, 2^61491584 is an apocalyptic number.

61491584 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61491584, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (81077760).

61491584 is an abundant number, since it is smaller than the sum of its proper divisors (100663936).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

61491584 is a wasteful number, since it uses less digits than its factorization.

61491584 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 416 (or 404 counting only the distinct ones).

The product of its digits is 34560, while the sum is 38.

The square root of 61491584 is about 7841.6569677588. The cubic root of 61491584 is about 394.7043324980.

The spelling of 61491584 in words is "sixty-one million, four hundred ninety-one thousand, five hundred eighty-four".