61881540 has 96 divisors (see below), whose sum is σ = 199148544. Its totient is φ = 14064000.

The previous prime is 61881529. The next prime is 61881557. The reversal of 61881540 is 4518816.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 105127 + ... + 105713.

It is an arithmetic number, because the mean of its divisors is an integer number (2074464).

Almost surely, 2^61881540 is an apocalyptic number.

61881540 is a gapful number since it is divisible by the number (60) 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 61881540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99574272).

61881540 is an abundant number, since it is smaller than the sum of its proper divisors (137267004).

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

61881540 is a wasteful number, since it uses less digits than its factorization.

61881540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 857 (or 855 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 33.

The square root of 61881540 is about 7866.4820599808. The cubic root of 61881540 is about 395.5369293763.

The spelling of 61881540 in words is "sixty-one million, eight hundred eighty-one thousand, five hundred forty".