21206154455 has 8 divisors (see below), whose sum is σ = 25499641632. Its totient is φ = 16930086048.

The previous prime is 21206154419. The next prime is 21206154479. The reversal of 21206154455 is 55445160212.

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

It is a cyclic number.

It is not a de Polignac number, because 21206154455 - 2¹⁶ = 21206088919 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 7 ways as a sum of consecutive naturals, for example, 4352012 + ... + 4356881.

It is an arithmetic number, because the mean of its divisors is an integer number (3187455204).

Almost surely, 2^21206154455 is an apocalyptic number.

21206154455 is a deficient number, since it is larger than the sum of its proper divisors (4293487177).

21206154455 is an equidigital number, since it uses as much as digits as its factorization.

21206154455 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8709385.

The product of its (nonzero) digits is 48000, while the sum is 35.

The spelling of 21206154455 in words is "twenty-one billion, two hundred six million, one hundred fifty-four thousand, four hundred fifty-five".