156211421 has 2 divisors, whose sum is σ = 156211422. Its totient is φ = 156211420.

The previous prime is 156211399. The next prime is 156211439. The reversal of 156211421 is 124112651.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 92371321 + 63840100 = 9611^2 + 7990^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-156211421 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (156211441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78105710 + 78105711.

It is an arithmetic number, because the mean of its divisors is an integer number (78105711).

Almost surely, 2^156211421 is an apocalyptic number.

It is an amenable number.

156211421 is a deficient number, since it is larger than the sum of its proper divisors (1).

156211421 is an equidigital number, since it uses as much as digits as its factorization.

156211421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 480, while the sum is 23.

The square root of 156211421 is about 12498.4567447345. The cubic root of 156211421 is about 538.5643403600.

The spelling of 156211421 in words is "one hundred fifty-six million, two hundred eleven thousand, four hundred twenty-one".