21437378497 has 8 divisors (see below), whose sum is σ = 21468148416. Its totient is φ = 21406629552.

The previous prime is 21437378483. The next prime is 21437378507. The reversal of 21437378497 is 79487373412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21437378497 is a prime.

It is a super-2 number, since 2×21437378497² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21437378477) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3650958 + ... + 3656824.

It is an arithmetic number, because the mean of its divisors is an integer number (2683518552).

Almost surely, 2^21437378497 is an apocalyptic number.

It is an amenable number.

21437378497 is a deficient number, since it is larger than the sum of its proper divisors (30769919).

21437378497 is a wasteful number, since it uses less digits than its factorization.

21437378497 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10487.

The product of its digits is 7112448, while the sum is 55.

The spelling of 21437378497 in words is "twenty-one billion, four hundred thirty-seven million, three hundred seventy-eight thousand, four hundred ninety-seven".