21049222657 has 4 divisors (see below), whose sum is σ = 21202866756. Its totient is φ = 20895578560.

The previous prime is 21049222619. The next prime is 21049222679. The reversal of 21049222657 is 75622294012.

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 13694616576 + 7354606081 = 117024^2 + 85759^2 .

It is a cyclic number.

It is not a de Polignac number, because 21049222657 - 2²³ = 21040834049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21049229657) 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, 76821844 + ... + 76822117.

It is an arithmetic number, because the mean of its divisors is an integer number (5300716689).

Almost surely, 2^21049222657 is an apocalyptic number.

It is an amenable number.

21049222657 is a deficient number, since it is larger than the sum of its proper divisors (153644099).

21049222657 is a wasteful number, since it uses less digits than its factorization.

21049222657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153644098.

The product of its (nonzero) digits is 120960, while the sum is 40.

The spelling of 21049222657 in words is "twenty-one billion, forty-nine million, two hundred twenty-two thousand, six hundred fifty-seven".