156621979 has 2 divisors, whose sum is σ = 156621980. Its totient is φ = 156621978.

The previous prime is 156621929. The next prime is 156622027. The reversal of 156621979 is 979126651.

It is a strong prime.

It is an emirp because it is prime and its reverse (979126651) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 156621979 - 2¹⁷ = 156490907 is a prime.

It is not a weakly prime, because it can be changed into another prime (156621929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78310989 + 78310990.

It is an arithmetic number, because the mean of its divisors is an integer number (78310990).

Almost surely, 2^156621979 is an apocalyptic number.

156621979 is a deficient number, since it is larger than the sum of its proper divisors (1).

156621979 is an equidigital number, since it uses as much as digits as its factorization.

156621979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 204120, while the sum is 46.

The square root of 156621979 is about 12514.8703149493. The cubic root of 156621979 is about 539.0357494907.

The spelling of 156621979 in words is "one hundred fifty-six million, six hundred twenty-one thousand, nine hundred seventy-nine".