21421960949 has 16 divisors (see below), whose sum is σ = 21675582720. Its totient is φ = 21170438400.

The previous prime is 21421960943. The next prime is 21421960981. The reversal of 21421960949 is 94906912412.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21421960949 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21421960943) 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, 24150584 + ... + 24151470.

It is an arithmetic number, because the mean of its divisors is an integer number (1354723920).

Almost surely, 2^21421960949 is an apocalyptic number.

It is an amenable number.

21421960949 is a deficient number, since it is larger than the sum of its proper divisors (253621771).

21421960949 is a wasteful number, since it uses less digits than its factorization.

21421960949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1780.

The product of its (nonzero) digits is 279936, while the sum is 47.

The spelling of 21421960949 in words is "twenty-one billion, four hundred twenty-one million, nine hundred sixty thousand, nine hundred forty-nine".