16401855 has 32 divisors (see below), whose sum is σ = 28055808. Its totient is φ = 8153600.

The previous prime is 16401839. The next prime is 16401871. The reversal of 16401855 is 55810461.

16401855 = 108² + 109² + ... + 369².

It is an interprime number because it is at equal distance from previous prime (16401839) and next prime (16401871).

It is not a de Polignac number, because 16401855 - 2⁴ = 16401839 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 33160 + ... + 33650.

It is an arithmetic number, because the mean of its divisors is an integer number (876744).

Almost surely, 2^16401855 is an apocalyptic number.

16401855 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

16401855 is a deficient number, since it is larger than the sum of its proper divisors (11653953).

16401855 is a wasteful number, since it uses less digits than its factorization.

16401855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 647.

The product of its (nonzero) digits is 4800, while the sum is 30.

The square root of 16401855 is about 4049.9203695875. The cubic root of 16401855 is about 254.0763973386.

The spelling of 16401855 in words is "sixteen million, four hundred one thousand, eight hundred fifty-five".