400123644665 has 16 divisors (see below), whose sum is σ = 484916226048. Its totient is φ = 316932552576.

The previous prime is 400123644647. The next prime is 400123644673. The reversal of 400123644665 is 566446321004.

It is a cyclic number.

It is not a de Polignac number, because 400123644665 - 2⁸ = 400123644409 is a prime.

It is a super-3 number, since 3×400123644665³ (a number of 36 digits) contains 333 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 500207 + ... + 1024916.

It is an arithmetic number, because the mean of its divisors is an integer number (30307264128).

Almost surely, 2^400123644665 is an apocalyptic number.

It is an amenable number.

400123644665 is a deficient number, since it is larger than the sum of its proper divisors (84792581383).

400123644665 is a wasteful number, since it uses less digits than its factorization.

400123644665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1525648.

The product of its (nonzero) digits is 414720, while the sum is 41.

Adding to 400123644665 its reverse (566446321004), we get a palindrome (966569965669).

The spelling of 400123644665 in words is "four hundred billion, one hundred twenty-three million, six hundred forty-four thousand, six hundred sixty-five".