21621960403 has 2 divisors, whose sum is σ = 21621960404. Its totient is φ = 21621960402.

The previous prime is 21621960377. The next prime is 21621960407. The reversal of 21621960403 is 30406912612.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21621960403 - 2²⁹ = 21085089491 is a prime.

It is not a weakly prime, because it can be changed into another prime (21621960407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10810980201 + 10810980202.

It is an arithmetic number, because the mean of its divisors is an integer number (10810980202).

Almost surely, 2^21621960403 is an apocalyptic number.

21621960403 is a deficient number, since it is larger than the sum of its proper divisors (1).

21621960403 is an equidigital number, since it uses as much as digits as its factorization.

21621960403 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15552, while the sum is 34.

The spelling of 21621960403 in words is "twenty-one billion, six hundred twenty-one million, nine hundred sixty thousand, four hundred three".