400537809661 has 32 divisors (see below), whose sum is σ = 461456714880. Its totient is φ = 344278636800.

The previous prime is 400537809589. The next prime is 400537809757. The reversal of 400537809661 is 166908735004.

It is a cyclic number.

It is not a de Polignac number, because 400537809661 - 2¹⁵ = 400537776893 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400537809361) 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, 4371855 + ... + 4462531.

It is an arithmetic number, because the mean of its divisors is an integer number (14420522340).

Almost surely, 2^400537809661 is an apocalyptic number.

It is an amenable number.

400537809661 is a deficient number, since it is larger than the sum of its proper divisors (60918905219).

400537809661 is a wasteful number, since it uses less digits than its factorization.

400537809661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91005.

The product of its (nonzero) digits is 1088640, while the sum is 49.

The spelling of 400537809661 in words is "four hundred billion, five hundred thirty-seven million, eight hundred nine thousand, six hundred sixty-one".