21590651 has 6 divisors (see below), whose sum is σ = 21737940. Its totient is φ = 21444236.

The previous prime is 21590633. The next prime is 21590659. The reversal of 21590651 is 15609512.

It is not a de Polignac number, because 21590651 - 2¹⁰ = 21589627 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21590659) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 51320 + ... + 51738.

It is an arithmetic number, because the mean of its divisors is an integer number (3622990).

Almost surely, 2^21590651 is an apocalyptic number.

21590651 is a deficient number, since it is larger than the sum of its proper divisors (147289).

21590651 is an frugal number, since it uses more digits than its factorization.

21590651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 873 (or 646 counting only the distinct ones).

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

The square root of 21590651 is about 4646.5741143341. The cubic root of 21590651 is about 278.4551443907.

The spelling of 21590651 in words is "twenty-one million, five hundred ninety thousand, six hundred fifty-one".