399969250561 has 4 divisors (see below), whose sum is σ = 399970520532. Its totient is φ = 399967980592.

The previous prime is 399969250543. The next prime is 399969250579. The reversal of 399969250561 is 165052969993.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is an interprime number because it is at equal distance from previous prime (399969250543) and next prime (399969250579).

It can be written as a sum of positive squares in 2 ways, for example, as 168842919025 + 231126331536 = 410905^2 + 480756^2 .

It is a cyclic number.

It is not a de Polignac number, because 399969250561 - 2¹³ = 399969242369 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 399969250493 and 399969250502.

It is not an unprimeable number, because it can be changed into a prime (399969250531) 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, 232155 + ... + 924031.

It is an arithmetic number, because the mean of its divisors is an integer number (99992630133).

Almost surely, 2^399969250561 is an apocalyptic number.

It is an amenable number.

399969250561 is a deficient number, since it is larger than the sum of its proper divisors (1269971).

399969250561 is an equidigital number, since it uses as much as digits as its factorization.

399969250561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1269970.

The product of its (nonzero) digits is 35429400, while the sum is 64.

The spelling of 399969250561 in words is "three hundred ninety-nine billion, nine hundred sixty-nine million, two hundred fifty thousand, five hundred sixty-one".