399644098561 has 4 divisors (see below), whose sum is σ = 410445290452. Its totient is φ = 388842906672.

The previous prime is 399644098493. The next prime is 399644098583. The reversal of 399644098561 is 165890446993.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 165890446993 = 26783 ⋅6193871.

It can be written as a sum of positive squares in 2 ways, for example, as 352503438400 + 47140660161 = 593720^2 + 217119^2 .

It is a cyclic number.

It is not a de Polignac number, because 399644098561 - 2¹³ = 399644090369 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 399644098493 and 399644098502.

It is not an unprimeable number, because it can be changed into a prime (399644098961) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5400595890 + ... + 5400595963.

It is an arithmetic number, because the mean of its divisors is an integer number (102611322613).

Almost surely, 2^399644098561 is an apocalyptic number.

It is an amenable number.

399644098561 is a deficient number, since it is larger than the sum of its proper divisors (10801191891).

399644098561 is a wasteful number, since it uses less digits than its factorization.

399644098561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10801191890.

The product of its (nonzero) digits is 50388480, while the sum is 64.

The spelling of 399644098561 in words is "three hundred ninety-nine billion, six hundred forty-four million, ninety-eight thousand, five hundred sixty-one".