21775001 has 4 divisors (see below), whose sum is σ = 21885732. Its totient is φ = 21664272.

The previous prime is 21774983. The next prime is 21775031. The reversal of 21775001 is 10057712.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18966025 + 2808976 = 4355^2 + 1676^2 .

It is a cyclic number.

It is not a de Polignac number, because 21775001 - 2¹⁰ = 21773977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21775031) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55070 + ... + 55463.

It is an arithmetic number, because the mean of its divisors is an integer number (5471433).

Almost surely, 2^21775001 is an apocalyptic number.

It is an amenable number.

21775001 is a deficient number, since it is larger than the sum of its proper divisors (110731).

21775001 is a wasteful number, since it uses less digits than its factorization.

21775001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110730.

The product of its (nonzero) digits is 490, while the sum is 23.

The square root of 21775001 is about 4666.3691452777. The cubic root of 21775001 is about 279.2454215271.

The spelling of 21775001 in words is "twenty-one million, seven hundred seventy-five thousand, one".