21551470417 has 16 divisors (see below), whose sum is σ = 22123584000. Its totient is φ = 20988025344.

The previous prime is 21551470337. The next prime is 21551470459. The reversal of 21551470417 is 71407415512.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21551470417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21551470117) 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, 3040884 + ... + 3047962.

It is an arithmetic number, because the mean of its divisors is an integer number (1382724000).

Almost surely, 2^21551470417 is an apocalyptic number.

It is an amenable number.

21551470417 is a deficient number, since it is larger than the sum of its proper divisors (572113583).

21551470417 is an equidigital number, since it uses as much as digits as its factorization.

21551470417 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7680.

The product of its (nonzero) digits is 39200, while the sum is 37.

Adding to 21551470417 its reverse (71407415512), we get a palindrome (92958885929).

The spelling of 21551470417 in words is "twenty-one billion, five hundred fifty-one million, four hundred seventy thousand, four hundred seventeen".