21537419 has 16 divisors (see below), whose sum is σ = 23522400. Its totient is φ = 19643904.

The previous prime is 21537391. The next prime is 21537427. The reversal of 21537419 is 91473512.

It is a cyclic number.

It is not a de Polignac number, because 21537419 - 2⁸ = 21537163 is a prime.

It is a super-2 number, since 2×21537419² = 927720834363122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21537479) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 109229 + ... + 109425.

It is an arithmetic number, because the mean of its divisors is an integer number (1470150).

Almost surely, 2^21537419 is an apocalyptic number.

21537419 is a deficient number, since it is larger than the sum of its proper divisors (1984981).

21537419 is a wasteful number, since it uses less digits than its factorization.

21537419 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 382.

The product of its digits is 7560, while the sum is 32.

The square root of 21537419 is about 4640.8424881696. The cubic root of 21537419 is about 278.2261112654.

The spelling of 21537419 in words is "twenty-one million, five hundred thirty-seven thousand, four hundred nineteen".