21201690 has 32 divisors (see below), whose sum is σ = 51114240. Its totient is φ = 5628224.

The previous prime is 21201689. The next prime is 21201707. The reversal of 21201690 is 9610212.

It is a super-2 number, since 2×21201690² = 899023317712200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5692 + ... + 8648.

It is an arithmetic number, because the mean of its divisors is an integer number (1597320).

Almost surely, 2^21201690 is an apocalyptic number.

21201690 is an abundant number, since it is smaller than the sum of its proper divisors (29912550).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21201690 is a wasteful number, since it uses less digits than its factorization.

21201690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3206.

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 21201690 is about 4604.5292919038. The cubic root of 21201690 is about 276.7728548369.

The spelling of 21201690 in words is "twenty-one million, two hundred one thousand, six hundred ninety".