666220440 has 32 divisors (see below), whose sum is σ = 1998661680. Its totient is φ = 177658752.

The previous prime is 666220433. The next prime is 666220453. The reversal of 666220440 is 44022666.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 666220398 and 666220407.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2775799 + ... + 2776038.

Almost surely, 2^666220440 is an apocalyptic number.

666220440 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

666220440 is an abundant number, since it is smaller than the sum of its proper divisors (1332441240).

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

666220440 is a wasteful number, since it uses less digits than its factorization.

666220440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5551851 (or 5551847 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 30.

The square root of 666220440 is about 25811.2463860233. The cubic root of 666220440 is about 873.3855137842.

The spelling of 666220440 in words is "six hundred sixty-six million, two hundred twenty thousand, four hundred forty".