21503230501 has 2 divisors, whose sum is σ = 21503230502. Its totient is φ = 21503230500.

The previous prime is 21503230493. The next prime is 21503230523. The reversal of 21503230501 is 10503230512.

It is an a-pointer prime, because the next prime (21503230523) can be obtained adding 21503230501 to its sum of digits (22).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11592828900 + 9910401601 = 107670^2 + 99551^2 .

It is a cyclic number.

It is not a de Polignac number, because 21503230501 - 2³ = 21503230493 is a prime.

It is a super-2 number, since 2×21503230501² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21503230571) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10751615250 + 10751615251.

It is an arithmetic number, because the mean of its divisors is an integer number (10751615251).

Almost surely, 2^21503230501 is an apocalyptic number.

It is an amenable number.

21503230501 is a deficient number, since it is larger than the sum of its proper divisors (1).

21503230501 is an equidigital number, since it uses as much as digits as its factorization.

21503230501 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 900, while the sum is 22.

It can be divided in two parts, 21503 and 230501, that added together give a square (252004 = 502²).

The spelling of 21503230501 in words is "twenty-one billion, five hundred three million, two hundred thirty thousand, five hundred one".