21962161 has 4 divisors (see below), whose sum is σ = 23651572. Its totient is φ = 20272752.

The previous prime is 21962107. The next prime is 21962173. The reversal of 21962161 is 16126912.

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 1168561 + 20793600 = 1081^2 + 4560^2 .

It is a cyclic number.

It is not a de Polignac number, because 21962161 - 2¹³ = 21953969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21962261) 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, 844686 + ... + 844711.

It is an arithmetic number, because the mean of its divisors is an integer number (5912893).

Almost surely, 2^21962161 is an apocalyptic number.

It is an amenable number.

21962161 is a deficient number, since it is larger than the sum of its proper divisors (1689411).

21962161 is a wasteful number, since it uses less digits than its factorization.

21962161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1689410.

The product of its digits is 1296, while the sum is 28.

The square root of 21962161 is about 4686.3803729531. The cubic root of 21962161 is about 280.0431948667.

The spelling of 21962161 in words is "twenty-one million, nine hundred sixty-two thousand, one hundred sixty-one".