21403220387 has 2 divisors, whose sum is σ = 21403220388. Its totient is φ = 21403220386.

The previous prime is 21403220273. The next prime is 21403220411. The reversal of 21403220387 is 78302230412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21403220387 - 2³⁴ = 4223351203 is a prime.

It is not a weakly prime, because it can be changed into another prime (21403220087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10701610193 + 10701610194.

It is an arithmetic number, because the mean of its divisors is an integer number (10701610194).

Almost surely, 2^21403220387 is an apocalyptic number.

21403220387 is a deficient number, since it is larger than the sum of its proper divisors (1).

21403220387 is an equidigital number, since it uses as much as digits as its factorization.

21403220387 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16128, while the sum is 32.

Adding to 21403220387 its reverse (78302230412), we get a palindrome (99705450799).

The spelling of 21403220387 in words is "twenty-one billion, four hundred three million, two hundred twenty thousand, three hundred eighty-seven".