16387840225 has 9 divisors (see below), whose sum is σ = 20321715603. Its totient is φ = 13109760120.

The previous prime is 16387840201. The next prime is 16387840229. The reversal of 16387840225 is 52204878361.

The square root of 16387840225 is 128015.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 5899622481 + 10488217744 = 76809^2 + 102412^2 .

It is not a de Polignac number, because 16387840225 - 2²⁵ = 16354285793 is a prime.

It is a super-2 number, since 2×16387840225² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16387840229) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 627274 + ... + 652876.

Almost surely, 2^16387840225 is an apocalyptic number.

16387840225 is the 128015-th square number.

16387840225 is the 64008-th centered octagonal number.

It is an amenable number.

16387840225 is a deficient number, since it is larger than the sum of its proper divisors (3933875378).

16387840225 is an frugal number, since it uses more digits than its factorization.

16387840225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51216 (or 25608 counting only the distinct ones).

The product of its (nonzero) digits is 645120, while the sum is 46.

The spelling of 16387840225 in words is "sixteen billion, three hundred eighty-seven million, eight hundred forty thousand, two hundred twenty-five".