21240430397 has 16 divisors (see below), whose sum is σ = 22073444352. Its totient is φ = 20424088320.

The previous prime is 21240430331. The next prime is 21240430399. The reversal of 21240430397 is 79303404212.

It is not a de Polignac number, because 21240430397 - 2¹⁶ = 21240364861 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21240430399) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2797268 + ... + 2804850.

It is an arithmetic number, because the mean of its divisors is an integer number (1379590272).

Almost surely, 2^21240430397 is an apocalyptic number.

It is an amenable number.

21240430397 is a deficient number, since it is larger than the sum of its proper divisors (833013955).

21240430397 is an equidigital number, since it uses as much as digits as its factorization.

21240430397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8668.

The product of its (nonzero) digits is 36288, while the sum is 35.

The spelling of 21240430397 in words is "twenty-one billion, two hundred forty million, four hundred thirty thousand, three hundred ninety-seven".