21221241994 has 4 divisors (see below), whose sum is σ = 31831862994. Its totient is φ = 10610620996.

The previous prime is 21221241959. The next prime is 21221242019. The reversal of 21221241994 is 49914212212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 12887925625 + 8333316369 = 113525^2 + 91287^2 .

It is a super-2 number, since 2×21221241994² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5305310497 + ... + 5305310500.

Almost surely, 2^21221241994 is an apocalyptic number.

21221241994 is a deficient number, since it is larger than the sum of its proper divisors (10610621000).

21221241994 is a wasteful number, since it uses less digits than its factorization.

21221241994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10610620999.

The product of its digits is 20736, while the sum is 37.

The spelling of 21221241994 in words is "twenty-one billion, two hundred twenty-one million, two hundred forty-one thousand, nine hundred ninety-four".