66621516 has 48 divisors (see below), whose sum is σ = 170176608. Its totient is φ = 20160000.

The previous prime is 66621509. The next prime is 66621551. The reversal of 66621516 is 61512666.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6016 + ... + 13016.

It is an arithmetic number, because the mean of its divisors is an integer number (3545346).

Almost surely, 2^66621516 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 66621516, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85088304).

66621516 is an abundant number, since it is smaller than the sum of its proper divisors (103555092).

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

66621516 is a wasteful number, since it uses less digits than its factorization.

66621516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7082 (or 7080 counting only the distinct ones).

The product of its digits is 12960, while the sum is 33.

The square root of 66621516 is about 8162.2004386072. The cubic root of 66621516 is about 405.3885738737.

The spelling of 66621516 in words is "sixty-six million, six hundred twenty-one thousand, five hundred sixteen".