406642640 has 40 divisors (see below), whose sum is σ = 978051240. Its totient is φ = 157047296.

The previous prime is 406642603. The next prime is 406642657. The reversal of 406642640 is 46246604.

It can be written as a sum of positive squares in 4 ways, for example, as 23892544 + 382750096 = 4888^2 + 19564^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 406642597 and 406642606.

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, 85319 + ... + 89958.

It is an arithmetic number, because the mean of its divisors is an integer number (24451281).

Almost surely, 2^406642640 is an apocalyptic number.

406642640 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

406642640 is an abundant number, since it is smaller than the sum of its proper divisors (571408600).

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

406642640 is a wasteful number, since it uses less digits than its factorization.

406642640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 175319 (or 175313 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 32.

The square root of 406642640 is about 20165.3822180488. The cubic root of 406642640 is about 740.8625442640.

The spelling of 406642640 in words is "four hundred six million, six hundred forty-two thousand, six hundred forty".