61668561 has 8 divisors (see below), whose sum is σ = 82352160. Its totient is φ = 41048672.

The previous prime is 61668557. The next prime is 61668583. The reversal of 61668561 is 16586616.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 61668561 - 2² = 61668557 is a prime.

It is a super-2 number, since 2×61668561² = 7606022831621442, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (61668461) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13620 + ... + 17573.

It is an arithmetic number, because the mean of its divisors is an integer number (10294020).

Almost surely, 2^61668561 is an apocalyptic number.

It is an amenable number.

61668561 is a deficient number, since it is larger than the sum of its proper divisors (20683599).

61668561 is a wasteful number, since it uses less digits than its factorization.

61668561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31855.

The product of its digits is 51840, while the sum is 39.

The square root of 61668561 is about 7852.9332736246. The cubic root of 61668561 is about 395.0826318608.

The spelling of 61668561 in words is "sixty-one million, six hundred sixty-eight thousand, five hundred sixty-one".