2121640236451 has 2 divisors, whose sum is σ = 2121640236452. Its totient is φ = 2121640236450.

The previous prime is 2121640236431. The next prime is 2121640236461. The reversal of 2121640236451 is 1546320461212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2121640236451 - 2⁷ = 2121640236323 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2121640236451.

It is not a weakly prime, because it can be changed into another prime (2121640236431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060820118225 + 1060820118226.

It is an arithmetic number, because the mean of its divisors is an integer number (1060820118226).

Almost surely, 2^{2121640236451} is an apocalyptic number.

2121640236451 is a deficient number, since it is larger than the sum of its proper divisors (1).

2121640236451 is an equidigital number, since it uses as much as digits as its factorization.

2121640236451 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 69120, while the sum is 37.

Adding to 2121640236451 its reverse (1546320461212), we get a palindrome (3667960697663).

The spelling of 2121640236451 in words is "two trillion, one hundred twenty-one billion, six hundred forty million, two hundred thirty-six thousand, four hundred fifty-one".