21420642050 has 24 divisors (see below), whose sum is σ = 39848314500. Its totient is φ = 8566983680.

The previous prime is 21420642031. The next prime is 21420642053. The reversal of 21420642050 is 5024602412.

It can be written as a sum of positive squares in 6 ways, for example, as 7439235001 + 13981407049 = 86251^2 + 118243^2 .

It is not an unprimeable number, because it can be changed into a prime (21420642053) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 354446 + ... + 410454.

Almost surely, 2^21420642050 is an apocalyptic number.

21420642050 is a deficient number, since it is larger than the sum of its proper divisors (18427672450).

21420642050 is a wasteful number, since it uses less digits than its factorization.

21420642050 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63670 (or 63665 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 26.

The spelling of 21420642050 in words is "twenty-one billion, four hundred twenty million, six hundred forty-two thousand, fifty".