21756801 has 16 divisors (see below), whose sum is σ = 31727808. Its totient is φ = 13152000.

The previous prime is 21756799. The next prime is 21756803. The reversal of 21756801 is 10865712.

It is an interprime number because it is at equal distance from previous prime (21756799) and next prime (21756803).

It is not a de Polignac number, because 21756801 - 2¹ = 21756799 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21756803) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19285 + ... + 20381.

It is an arithmetic number, because the mean of its divisors is an integer number (1982988).

Almost surely, 2^21756801 is an apocalyptic number.

It is an amenable number.

21756801 is a deficient number, since it is larger than the sum of its proper divisors (9971007).

21756801 is a wasteful number, since it uses less digits than its factorization.

21756801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1712.

The product of its (nonzero) digits is 3360, while the sum is 30.

The square root of 21756801 is about 4664.4186132893. The cubic root of 21756801 is about 279.1676001256.

The spelling of 21756801 in words is "twenty-one million, seven hundred fifty-six thousand, eight hundred one".