61539520 has 112 divisors (see below), whose sum is σ = 170005248. Its totient is φ = 20782080.

The previous prime is 61539503. The next prime is 61539521. The reversal of 61539520 is 2593516.

61539520 = T₁₁₇₆ + T₁₁₇₇ + ... + T₁₂₅₈.

It is a tau number, because it is divible by the number of its divisors (112).

It is a super-2 number, since 2×61539520² = 7574225043660800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (61539521) 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, 185755 + ... + 186085.

It is an arithmetic number, because the mean of its divisors is an integer number (1517904).

Almost surely, 2^61539520 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 61539520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85002624).

61539520 is an abundant number, since it is smaller than the sum of its proper divisors (108465728).

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

61539520 is a wasteful number, since it uses less digits than its factorization.

61539520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 438 (or 428 counting only the distinct ones).

The product of its (nonzero) digits is 8100, while the sum is 31.

The square root of 61539520 is about 7844.7128691878. The cubic root of 61539520 is about 394.8068702831.

The spelling of 61539520 in words is "sixty-one million, five hundred thirty-nine thousand, five hundred twenty".