21990945601 has 16 divisors (see below), whose sum is σ = 22925154240. Its totient is φ = 21069074880.

The previous prime is 21990945593. The next prime is 21990945703. The reversal of 21990945601 is 10654909912.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21990945601 - 2³ = 21990945593 is a prime.

It is a super-2 number, since 2×21990945601² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21990942601) 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, 2118115 + ... + 2128471.

It is an arithmetic number, because the mean of its divisors is an integer number (1432822140).

Almost surely, 2^21990945601 is an apocalyptic number.

It is an amenable number.

21990945601 is a deficient number, since it is larger than the sum of its proper divisors (934208639).

21990945601 is a wasteful number, since it uses less digits than its factorization.

21990945601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10944.

The product of its (nonzero) digits is 174960, while the sum is 46.

The spelling of 21990945601 in words is "twenty-one billion, nine hundred ninety million, nine hundred forty-five thousand, six hundred one".