66400425 has 192 divisors, whose sum is σ = 159989760. Its totient is φ = 26231040.

The previous prime is 66400423. The next prime is 66400427. The reversal of 66400425 is 52400466.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (66400423) and next prime (66400427).

It is not a de Polignac number, because 66400425 - 2¹ = 66400423 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66400423) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 1412752 + ... + 1412798.

It is an arithmetic number, because the mean of its divisors is an integer number (833280).

Almost surely, 2^66400425 is an apocalyptic number.

66400425 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

66400425 is an abundant number, since it is smaller than the sum of its proper divisors (93589335).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66400425 is a wasteful number, since it uses less digits than its factorization.

66400425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109 (or 98 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The square root of 66400425 is about 8148.6455929805. The cubic root of 66400425 is about 404.9396343499.

The spelling of 66400425 in words is "sixty-six million, four hundred thousand, four hundred twenty-five".