66402381 has 16 divisors (see below), whose sum is σ = 89812800. Its totient is φ = 43634688.

The previous prime is 66402367. The next prime is 66402409. The reversal of 66402381 is 18320466.

It is not a de Polignac number, because 66402381 - 2⁹ = 66401869 is a prime.

It is a super-2 number, since 2×66402381² = 8818552404938322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66402781) 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, 85965 + ... + 86733.

It is an arithmetic number, because the mean of its divisors is an integer number (5613300).

Almost surely, 2^66402381 is an apocalyptic number.

It is an amenable number.

66402381 is a deficient number, since it is larger than the sum of its proper divisors (23410419).

66402381 is a wasteful number, since it uses less digits than its factorization.

66402381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1148.

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 66402381 is about 8148.7656120421. The cubic root of 66402381 is about 404.9436104999.

The spelling of 66402381 in words is "sixty-six million, four hundred two thousand, three hundred eighty-one".