212139225 has 27 divisors (see below), whose sum is σ = 380356639. Its totient is φ = 113024400.

The previous prime is 212139139. The next prime is 212139229. The reversal of 212139225 is 522931212.

212139225 = T₄₃₁ + T₄₃₂ + ... + T₁₁₀₅.

It is a happy number.

The square root of 212139225 is 14565.

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., 76370121 + 135769104 = 8739^2 + 11652^2 .

It is not a de Polignac number, because 212139225 - 2⁹ = 212138713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (212139229) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 217990 + ... + 218960.

Almost surely, 2^212139225 is an apocalyptic number.

212139225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

212139225 is the 14565-th square number.

212139225 is the 7283-rd centered octagonal number.

It is an amenable number.

212139225 is a deficient number, since it is larger than the sum of its proper divisors (168217414).

212139225 is an frugal number, since it uses more digits than its factorization.

212139225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1958 (or 979 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The cubic root of 212139225 is about 596.4036957264.

The spelling of 212139225 in words is "two hundred twelve million, one hundred thirty-nine thousand, two hundred twenty-five".