21555242306 has 8 divisors (see below), whose sum is σ = 34820006844. Its totient is φ = 9948573360.

The previous prime is 21555242257. The next prime is 21555242377. The reversal of 21555242306 is 60324255512.

It can be written as a sum of positive squares in 2 ways, for example, as 18247957225 + 3307285081 = 135085^2 + 57509^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 414523865 + ... + 414523916.

Almost surely, 2^21555242306 is an apocalyptic number.

21555242306 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21555242306 is a deficient number, since it is larger than the sum of its proper divisors (13264764538).

21555242306 is a wasteful number, since it uses less digits than its factorization.

21555242306 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 829047796.

The product of its (nonzero) digits is 72000, while the sum is 35.

Adding to 21555242306 its reverse (60324255512), we get a palindrome (81879497818).

The spelling of 21555242306 in words is "twenty-one billion, five hundred fifty-five million, two hundred forty-two thousand, three hundred six".