15721423 has 2 divisors, whose sum is σ = 15721424. Its totient is φ = 15721422.

The previous prime is 15721421. The next prime is 15721427. The reversal of 15721423 is 32412751.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 15721423 - 2¹ = 15721421 is a prime.

It is a super-2 number, since 2×15721423² = 494326282289858, which contains 22 as substring.

Together with 15721421, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15721421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7860711 + 7860712.

It is an arithmetic number, because the mean of its divisors is an integer number (7860712).

Almost surely, 2^15721423 is an apocalyptic number.

15721423 is a deficient number, since it is larger than the sum of its proper divisors (1).

15721423 is an equidigital number, since it uses as much as digits as its factorization.

15721423 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1680, while the sum is 25.

The square root of 15721423 is about 3965.0249683955. The cubic root of 15721423 is about 250.5132017749.

The spelling of 15721423 in words is "fifteen million, seven hundred twenty-one thousand, four hundred twenty-three".