21437378507 has 2 divisors, whose sum is σ = 21437378508. Its totient is φ = 21437378506.

The previous prime is 21437378483. The next prime is 21437378561. The reversal of 21437378507 is 70587373412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21437378507 - 2¹⁶ = 21437312971 is a prime.

It is a super-2 number, since 2×21437378507² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21437378707) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10718689253 + 10718689254.

It is an arithmetic number, because the mean of its divisors is an integer number (10718689254).

Almost surely, 2^21437378507 is an apocalyptic number.

21437378507 is a deficient number, since it is larger than the sum of its proper divisors (1).

21437378507 is an equidigital number, since it uses as much as digits as its factorization.

21437378507 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 987840, while the sum is 47.

The spelling of 21437378507 in words is "twenty-one billion, four hundred thirty-seven million, three hundred seventy-eight thousand, five hundred seven".