61661512 has 48 divisors (see below), whose sum is σ = 128847600. Its totient is φ = 27434400.

The previous prime is 61661503. The next prime is 61661513. The reversal of 61661512 is 21516616.

It is a super-3 number, since 3×61661512³ (a number of 24 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (61661513) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 443539 + ... + 443677.

It is an arithmetic number, because the mean of its divisors is an integer number (2684325).

Almost surely, 2^61661512 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61661512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (64423800).

61661512 is an abundant number, since it is smaller than the sum of its proper divisors (67186088).

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

61661512 is a wasteful number, since it uses less digits than its factorization.

61661512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 298 (or 223 counting only the distinct ones).

The product of its digits is 2160, while the sum is 28.

The square root of 61661512 is about 7852.4844476127. The cubic root of 61661512 is about 395.0675780335.

Subtracting from 61661512 its reverse (21516616), we obtain a square (40144896 = 6336²).

It can be divided in two parts, 616 and 61512, that added together give a triangular number (62128 = T₃₅₂).

The spelling of 61661512 in words is "sixty-one million, six hundred sixty-one thousand, five hundred twelve".