21026172605 has 8 divisors (see below), whose sum is σ = 25232435712. Its totient is φ = 16820252368.

The previous prime is 21026172599. The next prime is 21026172653. The reversal of 21026172605 is 50627162012.

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 21026172605 - 2⁴ = 21026172589 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, 77432 + ... + 219198.

It is an arithmetic number, because the mean of its divisors is an integer number (3154054464).

Almost surely, 2^21026172605 is an apocalyptic number.

It is an amenable number.

21026172605 is a deficient number, since it is larger than the sum of its proper divisors (4206263107).

21026172605 is a wasteful number, since it uses less digits than its factorization.

21026172605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171435.

The product of its (nonzero) digits is 10080, while the sum is 32.

The spelling of 21026172605 in words is "twenty-one billion, twenty-six million, one hundred seventy-two thousand, six hundred five".