213621538 has 16 divisors (see below), whose sum is σ = 348962040. Its totient is φ = 97485696.

The previous prime is 213621509. The next prime is 213621547. The reversal of 213621538 is 835126312.

It can be written as a sum of positive squares in 4 ways, for example, as 157176369 + 56445169 = 12537^2 + 7513^2 .

It is a super-2 number, since 2×213621538² = 91268322994970888, which contains 22 as substring.

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, 43845 + ... + 48472.

Almost surely, 2^213621538 is an apocalyptic number.

213621538 is a deficient number, since it is larger than the sum of its proper divisors (135340502).

213621538 is a wasteful number, since it uses less digits than its factorization.

213621538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92421.

The product of its digits is 8640, while the sum is 31.

The square root of 213621538 is about 14615.7975492273. The cubic root of 213621538 is about 597.7895871621.

The spelling of 213621538 in words is "two hundred thirteen million, six hundred twenty-one thousand, five hundred thirty-eight".