213621431 has 2 divisors, whose sum is σ = 213621432. Its totient is φ = 213621430.

The previous prime is 213621409. The next prime is 213621437. The reversal of 213621431 is 134126312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 213621431 - 2⁶ = 213621367 is a prime.

It is a super-2 number, since 2×213621431² = 91268231564975522, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 213621397 and 213621406.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213621437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106810715 + 106810716.

It is an arithmetic number, because the mean of its divisors is an integer number (106810716).

Almost surely, 2^213621431 is an apocalyptic number.

213621431 is a deficient number, since it is larger than the sum of its proper divisors (1).

213621431 is an equidigital number, since it uses as much as digits as its factorization.

213621431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 864, while the sum is 23.

The square root of 213621431 is about 14615.7938888040. The cubic root of 213621431 is about 597.7894873540.

Adding to 213621431 its reverse (134126312), we get a palindrome (347747743).

The spelling of 213621431 in words is "two hundred thirteen million, six hundred twenty-one thousand, four hundred thirty-one".