209142536 has 8 divisors (see below), whose sum is σ = 392142270. Its totient is φ = 104571264.

The previous prime is 209142503. The next prime is 209142539. The reversal of 209142536 is 635241902.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 201469636 + 7672900 = 14194^2 + 2770^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×209142536² = 87481200729022592, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (209142539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13071401 + ... + 13071416.

Almost surely, 2^209142536 is an apocalyptic number.

It is an amenable number.

209142536 is a deficient number, since it is larger than the sum of its proper divisors (182999734).

209142536 is a wasteful number, since it uses less digits than its factorization.

209142536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26142823 (or 26142819 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 209142536 is about 14461.7611652247. The cubic root of 209142536 is about 593.5820918232.

The spelling of 209142536 in words is "two hundred nine million, one hundred forty-two thousand, five hundred thirty-six".