66969890 has 16 divisors (see below), whose sum is σ = 129818808. Its totient is φ = 24727296.

The previous prime is 66969871. The next prime is 66969893. The reversal of 66969890 is 9896966.

It can be written as a sum of positive squares in 4 ways, for example, as 16999129 + 49970761 = 4123^2 + 7069^2 .

It is a super-2 number, since 2×66969890² = 8969932333224200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66969893) 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, 257447 + ... + 257706.

Almost surely, 2^66969890 is an apocalyptic number.

66969890 is a deficient number, since it is larger than the sum of its proper divisors (62848918).

66969890 is a wasteful number, since it uses less digits than its factorization.

66969890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 515173.

The product of its (nonzero) digits is 1259712, while the sum is 53.

The square root of 66969890 is about 8183.5133041989. The cubic root of 66969890 is about 406.0939585334.

The spelling of 66969890 in words is "sixty-six million, nine hundred sixty-nine thousand, eight hundred ninety".