21701949 has 16 divisors (see below), whose sum is σ = 30307200. Its totient is φ = 13787136.

The previous prime is 21701941. The next prime is 21701959. The reversal of 21701949 is 94910712.

It is not a de Polignac number, because 21701949 - 2³ = 21701941 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21701941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27837 + ... + 28605.

It is an arithmetic number, because the mean of its divisors is an integer number (1894200).

Almost surely, 2^21701949 is an apocalyptic number.

It is an amenable number.

21701949 is a deficient number, since it is larger than the sum of its proper divisors (8605251).

21701949 is a wasteful number, since it uses less digits than its factorization.

21701949 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1204.

The product of its (nonzero) digits is 4536, while the sum is 33.

The square root of 21701949 is about 4658.5350701696. The cubic root of 21701949 is about 278.9327955707.

The spelling of 21701949 in words is "twenty-one million, seven hundred one thousand, nine hundred forty-nine".