16401635604 has 18 divisors (see below), whose sum is σ = 41459690090. Its totient is φ = 5467211856.

The previous prime is 16401635597. The next prime is 16401635611. The reversal of 16401635604 is 40653610461.

It is a happy number.

16401635604 is a `hidden beast` number, since 1 + 6 + 4 + 0 + 16 + 35 + 604 = 666.

It is an interprime number because it is at equal distance from previous prime (16401635597) and next prime (16401635611).

It can be written as a sum of positive squares in only one way, i.e., 16383488004 + 18147600 = 127998^2 + 4260^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-3 number, since 3×16401635604³ (a number of 32 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 455600989 = 16401635604 / (1 + 6 + 4 + 0 + 1 + 6 + 3 + 5 + 6 + 0 + 4).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 227800459 + ... + 227800530.

Almost surely, 2^16401635604 is an apocalyptic number.

It is an amenable number.

16401635604 is an abundant number, since it is smaller than the sum of its proper divisors (25058054486).

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

16401635604 is a wasteful number, since it uses less digits than its factorization.

16401635604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 455600999 (or 455600994 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The spelling of 16401635604 in words is "sixteen billion, four hundred one million, six hundred thirty-five thousand, six hundred four".