1642518221 has 2 divisors, whose sum is σ = 1642518222. Its totient is φ = 1642518220.

The previous prime is 1642518209. The next prime is 1642518253. The reversal of 1642518221 is 1228152461.

It is an a-pointer prime, because the next prime (1642518253) can be obtained adding 1642518221 to its sum of digits (32).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1483405225 + 159112996 = 38515^2 + 12614^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1642518221 is a prime.

It is a super-2 number, since 2×1642518221² = 5395732212634009682, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1642518281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 821259110 + 821259111.

It is an arithmetic number, because the mean of its divisors is an integer number (821259111).

Almost surely, 2^1642518221 is an apocalyptic number.

It is an amenable number.

1642518221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1642518221 is an equidigital number, since it uses as much as digits as its factorization.

1642518221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7680, while the sum is 32.

The square root of 1642518221 is about 40527.9930541842. The cubic root of 1642518221 is about 1179.8769911514.

The spelling of 1642518221 in words is "one billion, six hundred forty-two million, five hundred eighteen thousand, two hundred twenty-one".