21421644202415 has 16 divisors (see below), whose sum is σ = 26103745832736. Its totient is φ = 16872955776000.

The previous prime is 21421644202403. The next prime is 21421644202429. The reversal of 21421644202415 is 51420244612412.

It is not a de Polignac number, because 21421644202415 - 2¹⁸ = 21421643940271 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 51183386 + ... + 51600215.

It is an arithmetic number, because the mean of its divisors is an integer number (1631484114546).

Almost surely, 2^{21421644202415} is an apocalyptic number.

21421644202415 is a deficient number, since it is larger than the sum of its proper divisors (4682101630321).

21421644202415 is a wasteful number, since it uses less digits than its factorization.

21421644202415 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102784250.

The product of its (nonzero) digits is 122880, while the sum is 38.

Adding to 21421644202415 its reverse (51420244612412), we get a palindrome (72841888814827).

The spelling of 21421644202415 in words is "twenty-one trillion, four hundred twenty-one billion, six hundred forty-four million, two hundred two thousand, four hundred fifteen".