61521408 has 180 divisors, whose sum is σ = 194697360. Its totient is φ = 18690048.

The previous prime is 61521403. The next prime is 61521409. The reversal of 61521408 is 80412516.

61521408 is a `hidden beast` number, since 615 + 2 + 1 + 40 + 8 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61521401) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 778713 + ... + 778791.

It is an arithmetic number, because the mean of its divisors is an integer number (1081652).

Almost surely, 2^61521408 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 61521408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97348680).

61521408 is an abundant number, since it is smaller than the sum of its proper divisors (133175952).

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

61521408 is a wasteful number, since it uses less digits than its factorization.

61521408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129 (or 97 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 61521408 is about 7843.5583761454. The cubic root of 61521408 is about 394.7681339629.

The spelling of 61521408 in words is "sixty-one million, five hundred twenty-one thousand, four hundred eight".