66061989 has 24 divisors (see below), whose sum is σ = 109765760. Its totient is φ = 37503648.

The previous prime is 66061987. The next prime is 66061999. The reversal of 66061989 is 98916066.

It is not a de Polignac number, because 66061989 - 2¹ = 66061987 is a prime.

It is a super-2 number, since 2×66061989² = 8728372781272242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66061987) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6552 + ... + 13230.

Almost surely, 2^66061989 is an apocalyptic number.

It is an amenable number.

66061989 is a deficient number, since it is larger than the sum of its proper divisors (43703771).

66061989 is a wasteful number, since it uses less digits than its factorization.

66061989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6849 (or 6846 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 45.

The square root of 66061989 is about 8127.8526684482. The cubic root of 66061989 is about 404.2504839002.

The spelling of 66061989 in words is "sixty-six million, sixty-one thousand, nine hundred eighty-nine".