20151821423 has 2 divisors, whose sum is σ = 20151821424. Its totient is φ = 20151821422.

The previous prime is 20151821411. The next prime is 20151821479. The reversal of 20151821423 is 32412815102.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20151821423 - 2¹⁴ = 20151805039 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20151221423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10075910711 + 10075910712.

It is an arithmetic number, because the mean of its divisors is an integer number (10075910712).

Almost surely, 2^20151821423 is an apocalyptic number.

20151821423 is a deficient number, since it is larger than the sum of its proper divisors (1).

20151821423 is an equidigital number, since it uses as much as digits as its factorization.

20151821423 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3840, while the sum is 29.

The spelling of 20151821423 in words is "twenty billion, one hundred fifty-one million, eight hundred twenty-one thousand, four hundred twenty-three".