21965601 has 8 divisors (see below), whose sum is σ = 33471424. Its totient is φ = 12551760.

The previous prime is 21965599. The next prime is 21965623. The reversal of 21965601 is 10656912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21965601 - 2¹ = 21965599 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21965651) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 522970 + ... + 523011.

It is an arithmetic number, because the mean of its divisors is an integer number (4183928).

Almost surely, 2^21965601 is an apocalyptic number.

21965601 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21965601 is a deficient number, since it is larger than the sum of its proper divisors (11505823).

21965601 is a wasteful number, since it uses less digits than its factorization.

21965601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1045991.

The product of its (nonzero) digits is 3240, while the sum is 30.

The square root of 21965601 is about 4686.7473795800. The cubic root of 21965601 is about 280.0578154422.

The spelling of 21965601 in words is "twenty-one million, nine hundred sixty-five thousand, six hundred one".