21049497 has 16 divisors (see below), whose sum is σ = 35639680. Its totient is φ = 12028176.

The previous prime is 21049493. The next prime is 21049499. The reversal of 21049497 is 79494012.

It is not a de Polignac number, because 21049497 - 2² = 21049493 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21049493) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 55498 + ... + 55875.

It is an arithmetic number, because the mean of its divisors is an integer number (2227480).

Almost surely, 2^21049497 is an apocalyptic number.

21049497 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21049497 is a deficient number, since it is larger than the sum of its proper divisors (14590183).

21049497 is a wasteful number, since it uses less digits than its factorization.

21049497 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111389 (or 111383 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 21049497 is about 4587.9730818740. The cubic root of 21049497 is about 276.1090070362.

The spelling of 21049497 in words is "twenty-one million, forty-nine thousand, four hundred ninety-seven".