16401504 has 48 divisors (see below), whose sum is σ = 49206528. Its totient is φ = 4685952.

The previous prime is 16401499. The next prime is 16401523. The reversal of 16401504 is 40510461.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11532 + ... + 12875.

It is an arithmetic number, because the mean of its divisors is an integer number (1025136).

Almost surely, 2^16401504 is an apocalyptic number.

16401504 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

16401504 is an abundant number, since it is smaller than the sum of its proper divisors (32805024).

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

16401504 is a wasteful number, since it uses less digits than its factorization.

16401504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24427 (or 24419 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 16401504 is about 4049.8770351703. The cubic root of 16401504 is about 254.0745849125.

Adding to 16401504 its reverse (40510461), we get a palindrome (56911965).

The spelling of 16401504 in words is "sixteen million, four hundred one thousand, five hundred four".