61385721 has 16 divisors (see below), whose sum is σ = 85700160. Its totient is φ = 39032000.

The previous prime is 61385717. The next prime is 61385741. The reversal of 61385721 is 12758316.

It is a cyclic number.

It is not a de Polignac number, because 61385721 - 2² = 61385717 is a prime.

It is a super-3 number, since 3×61385721³ (a number of 24 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (61385711) 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, 2971 + ... + 11471.

It is an arithmetic number, because the mean of its divisors is an integer number (5356260).

Almost surely, 2^61385721 is an apocalyptic number.

It is an amenable number.

61385721 is a deficient number, since it is larger than the sum of its proper divisors (24314439).

61385721 is a wasteful number, since it uses less digits than its factorization.

61385721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8616.

The product of its digits is 10080, while the sum is 33.

The square root of 61385721 is about 7834.9040198333. The cubic root of 61385721 is about 394.4776966802.

The spelling of 61385721 in words is "sixty-one million, three hundred eighty-five thousand, seven hundred twenty-one".