66616431 has 32 divisors (see below), whose sum is σ = 106176000. Its totient is φ = 37114560.

The previous prime is 66616409. The next prime is 66616439. The reversal of 66616431 is 13461666.

It is not a de Polignac number, because 66616431 - 2¹³ = 66608239 is a prime.

It is a super-2 number, since 2×66616431² = 8875497758355522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 66616392 and 66616401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66616439) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 41400 + ... + 42978.

It is an arithmetic number, because the mean of its divisors is an integer number (3318000).

Almost surely, 2^66616431 is an apocalyptic number.

66616431 is a deficient number, since it is larger than the sum of its proper divisors (39559569).

66616431 is a wasteful number, since it uses less digits than its factorization.

66616431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1644 (or 1630 counting only the distinct ones).

The product of its digits is 15552, while the sum is 33.

The square root of 66616431 is about 8161.8889357795. Note that the first 3 decimals coincide. The cubic root of 66616431 is about 405.3782596215.

The spelling of 66616431 in words is "sixty-six million, six hundred sixteen thousand, four hundred thirty-one".