21213611013451 has 2 divisors, whose sum is σ = 21213611013452. Its totient is φ = 21213611013450.

The previous prime is 21213611013433. The next prime is 21213611013457. The reversal of 21213611013451 is 15431011631212.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21213611013451 - 2²³ = 21213602624843 is a prime.

It is not a weakly prime, because it can be changed into another prime (21213611013457) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606805506725 + 10606805506726.

It is an arithmetic number, because the mean of its divisors is an integer number (10606805506726).

Almost surely, 2^{21213611013451} is an apocalyptic number.

21213611013451 is a deficient number, since it is larger than the sum of its proper divisors (1).

21213611013451 is an equidigital number, since it uses as much as digits as its factorization.

21213611013451 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4320, while the sum is 31.

Adding to 21213611013451 its reverse (15431011631212), we get a palindrome (36644622644663).

The spelling of 21213611013451 in words is "twenty-one trillion, two hundred thirteen billion, six hundred eleven million, thirteen thousand, four hundred fifty-one".