21026721675 has 24 divisors (see below), whose sum is σ = 35703756976. Its totient is φ = 10911162240.

The previous prime is 21026721649. The next prime is 21026721691. The reversal of 21026721675 is 57612762012.

It is not a de Polignac number, because 21026721675 - 2¹⁰ = 21026720651 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3785824 + ... + 3791373.

Almost surely, 2^21026721675 is an apocalyptic number.

21026721675 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21026721675 is a deficient number, since it is larger than the sum of its proper divisors (14677035301).

21026721675 is a wasteful number, since it uses less digits than its factorization.

21026721675 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7577247 (or 7577242 counting only the distinct ones).

The product of its (nonzero) digits is 70560, while the sum is 39.

The spelling of 21026721675 in words is "twenty-one billion, twenty-six million, seven hundred twenty-one thousand, six hundred seventy-five".