21955601 has 4 divisors (see below), whose sum is σ = 22233600. Its totient is φ = 21677604.

The previous prime is 21955589. The next prime is 21955613. The reversal of 21955601 is 10655912.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (21955589) and next prime (21955613).

It is a cyclic number.

It is not a de Polignac number, because 21955601 - 2¹⁰ = 21954577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21955631) 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, 138881 + ... + 139038.

It is an arithmetic number, because the mean of its divisors is an integer number (5558400).

Almost surely, 2^21955601 is an apocalyptic number.

21955601 is the 2096-th centered decagonal number.

It is an amenable number.

21955601 is a deficient number, since it is larger than the sum of its proper divisors (277999).

21955601 is an equidigital number, since it uses as much as digits as its factorization.

21955601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 277998.

The product of its (nonzero) digits is 2700, while the sum is 29.

The square root of 21955601 is about 4685.6804201738. The cubic root of 21955601 is about 280.0153095371.

The spelling of 21955601 in words is "twenty-one million, nine hundred fifty-five thousand, six hundred one".